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One of the most probable scenarios of the NO-CO reaction on the (111) surface of noble metals includes reversible NO and CO adsorption, NO dissociation, N-2 desorption, and CO2 formation due to reaction between adsorbed CO and 0 species. Adopting this scheme, we analyze the reaction kinetics in the situation when the surface contains steps. Employing the mean-field kinetic equations with the kinetic parameters corresponding to the case when the adsorbate coverage is high and the reaction rate is limited by NO dissociation, we show that the contribution of steps to the reaction rate may be appreciable. The adsorbate-diffusion-mediated communication between terraces and steps can play a constructive role in the reaction, i.e., the reaction rate may be higher with than without communication. In addition, we present Monte Carlo simulations demonstrating that, due to limitations in the rate of N diffusion, the adsorbate distribution along the surface may be non-uniform with the largest N coverage near steps. Such reaction regimes are found to be possible even for relatively high rates of N diffusion (e.g., in the case when the ratio of the rates of N jumps and CO or NO impingement is about 10(4)). The implications of these findings for the understanding of the specifics of the reaction under consideration are briefly discussed.

Hereditary nonpolyposis colorectal cancer (HNPCC) and familial adenomatosis polyposis (FAP) are well-known high-risk cancer syndromes. Hereditary colorectal cancer (HCRC) with at least three relatives with colorectal cancer and a dominant pattern of inheritance but with no specifications for age at onset and two close relatives with colorectal cancer (TCR) are other forms of familial clustering known to carry an increased risk of the disease. The frequency of the total burden of familial colorectal cancer is not well known. We therefore investigated the family history of 400/411 (97%) eligible patients with recently diagnosed colorectal cancer in Vastmanland county, Sweden, during a 3-year period. Records or death certificates confirmed the diagnoses of relatives. Five patients (1.2%, 95% CI 0.15–2.2) were diagnosed as having HNPCC, eight (1.9%, 95% CI 0.6–3.2) as having HCRC and thirty-four (8.3%, 95% CI 5.6–11.0) were identified as having TCR. In total, 47 patients (11.4%, 95% CI 8.3–14.5) were found to have a contributing familial background. The implication is thus that every ninth patient with colorectal cancer represents a highly or intermediately increased risk of the disease among relatives. We conclude that the low frequency of individuals identified by family history alone makes the establishment of surveillance programs feasible.

Flow reactor experiments and XPS measurements were used to investigate the observed decrease in activity of Pt/Al2O3 and Pt/BaO/Al2O3 catalysts during reaction conditions. The reactions studied were NO(g)+1/2O2(g)⇔NO2(g). The influence of platinum dispersion on activity and on the activity decrease with time was also studied. When the Pt/Al2O3 catalyst was exposed to NO2 (350°C), the NO2 dissociation rate decreased. This activity decrease with time was also studied with XPS and it is suggested that it was due to platinum oxide formation. Further, when the platinum dispersion was increased, the platinum activity decreased and the reason may be that small platinum particles more easily form oxides. According to XPS measurements platinum supported on BaO/Al2O3 gave a higher concentration of platinum oxide after NO2 exposure compared to what was found for Pt supported on only Al2O3. Flow reactor experiments also showed that Pt/BaO/Al2O3 was less active, both for oxidation of NO and for reduction of NO2, than Pt/Al2O3 was and one possible explanation for this is the fact that platinum on BaO/Al2O3 forms more oxides.

A mean field model, for storage and desorption of NOx in a Pt/BaO/Al2O3 catalyst is developed using data from flow reactor experiments. This relatively complex system is divided into five smaller sub-systems and the model is divided into the following steps: (i) NO oxidation on Pt/Al2O3; (ii) NO oxidation on Pt/BaO/Al2O3; (iii) NOx storage on BaO/Al2O3; (iv) NOx storage on Pt/BaO/Al2O3 with thermal regeneration and (v) NOx storage on Pt/BaO/Al2O3 with regeneration using C3H6. In this paper, we focus on the last sub-system. The kinetic model for NO, storage on Pt/BaO/Al2O3 was constructed with kinetic parameters obtained from the NO oxidation model together with a NO, storage model on BaO/Al2O3. This model was not sufficient to describe the NO, storage experiments for the Pt/BaO/Al2O3, because the NO, desorption in TPD experiments was larger for Pt/BaO/Al2O3, compared to BaO/Al2O3. The model was therefore modified by adding a reversible spill-over step. Further, the model was validated with additional experiments, which showed that NO significantly promoted desorption of NOx from Pt/BaO/Al2O3. To this NOx storage model, additional steps were added to describe the reduction by hydrocarbon in experiments with NO2 and C3H6. The main reactions for continuous reduction of NOx occurs on Pt by reactions between hydrocarbon species and NO in the model. The model is also able to describe the reduction phase, the storage and NO breakthrough peaks, observed in experiments.

We developed a procedure for aqueous ion exchange to obtain different Cu loadings of Cu/SAPO-34 (between 0 and 2.6 wt %.) The catalysts were washcoated on monoliths and characterised with respect to their activity and selectivity under standard selective catalytic reduction (SCR), fast SCR, NH3 oxidation and NO oxidation reactions. They were further characterised using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), H2-temperature programmed reduction (H2-TPR), ultraviolet (UV)-vis spectroscopy and NH3 adsorption. As expected, activity of all reactions increased with copper loading, due to increased number of active sites. However, the N2O formation during standard and fast SCR yielded interesting mechanistic information. We observed that N2O formation at low temperature increased with copper loading for the standard SCR reaction, while it decreased for fast SCR. The low-temperature N2O formation during fast SCR thus occurs predominantly over Brønsted sites. Species responsible for N2O formation during standard SCR, on the other hand, are formed on the copper sites. We further found that the fast SCR reaction occurs to a significant extent even over the H/SAPO-34 form. The Brønsted sites in SAPO-34 are thus active for the fast SCR reaction.

To the Editor During the past decade, CT technique has developed rapidly, with the main goal of reducing radiation dose while maintaining image quality. Since large diagnostic accuracy studies are at great risk of being already outdated at the time of publication, simpler clinical feasibility phantom studies1 and diagnostic acceptability studies have become important tools for evaluation and comparison of the new techniques. The study by Love et al1 is a phantom study and is therefore limited when it comes to evaluation of specific clinically relevant aspects such as potential influence of beam-hardening artefacts on diagnostic accuracy in subarachnoidal haemorrhage, as described by Awai et al.2 Such evaluation is clearly outside the scope of the study. In our study, the bone-mimicking ring was instead used to introduce noise in the phantom and thereby more closely resemble the clinical situation with respect to low-contrast resolution, which is clinically very important as Awai et al point out. In the brain, the difference in CT numbers between grey matter and white matter is normally in the range 5–10 HU. Although visual differentiation of adjacent structures is dependent on standard deviation (SD) of noise in the images, the relationship is far more complex, which is why our study also evaluates noise-power spectra and subjective evaluation. It is to us unclear on which scientific basis Awai et al argue that “to detect such minute CT number differences between the grey matter and white matter, the image noise must be less than at least 5 HU.” Nevertheless, as seen in Table 3, noise levels (SD) are below or close to 5 HU when applying the advanced IR algorithms at 48 mGy and even in some cases at 12 mGy. Despite increasing use of clinical guidelines for CT neuroimaging in clinical situations, such as in trauma, stroke, headache and dementia, utilization of CT is increasing in all age groups—with only a small minority of patients having detectable pathology. Assuming that currently employed clinical CT protocols already are optimized according to the as low as reasonably achievable principle, introduction of a new technique that improves image quality should primarily be used to reduce radiation dose so that image quality remains unchanged. From a clinical and radiation perspective, CT image quality higher than that necessary for the clinical task should not be pursued. We do not claim that our results can directly be used to change current clinical protocols, but our conclusions can be used as a base for clinical diagnostic acceptability studies aiming at further dose reduction while retaining image quality. The authors

In Sweden, individuals affected by severe stroke are treated in specialized stroke units. In these units, patients are attended by a multiprofessional team with a focus on care in the acute phase of stroke, rehabilitation phase, and palliative phase. Caring for patients with such a large variety in condition and symptoms might be an extra challenge for the team. Today, there is a lack of knowledge in team experiences of the dilemmas that appear and the consequences that emerge. Therefore, the purpose of this article was to study ethical dilemmas, different approaches, and what consequences they had among healthcare professionals working with the dying patients with stroke in acute stroke units. Forty-one healthcare professionals working in a stroke team were interviewed either in focus groups or individually. The data were transcribed verbatim and analyzed using content analysis. The ethical dilemmas that appeared were depending on "nondecisions" about palliative care or discontinuation of treatments. The lack of decision made the team members act based on their own individual skills, because of the absence of common communication tools. When a decision was made, the healthcare professionals had "problems holding to the decision." The devised and applied plans could be revalued, which was described as a setback to nondecisions again. The underlying problem and theme was "communication barriers," a consequence related to the absence of common skills and consensus among the value system. This study highlights the importance of palliative care knowledge and skills, even for patients experiencing severe stroke. To make a decision and to hold on to that is a presupposition in creating a credible care plan. However, implementing a common set of values based on palliative care with symptom control and quality of life might minimize the risk of the communication barrier that may arise and increases the ability to create a healthcare that is meaningful and dignified.

The effect of various fuel-cut agings, on a Volvo Cars 4-cylinder gasoline engine, with bimetallic three-way catalysts (TWCs) was examined. Deactivation during retardation fuel-cut (low load) and acceleration fuel-cut (high load, e.g. gearshift or traction control) was compared to aging at =1. Three-way catalysts were aged on an engine bench comparing two fuel-cut strategies and their impact on of the life and performance of the catalysts. In greater detail, the catalytic activity, stability and selectivity were studied. Furthermore, the catalysts were thoroughly analyzed using light-off and oxygen storage capacity measurements. The emission conversion as a function of various lambda values and loads was also determined. Fresh and 40-hour aged samples showed that the acceleration fuel-cut was the strategy that had the highest contribution towards the total deactivation of the catalyst system. Also, the retardation fuel-cut was found to be detrimental to the catalyst system but not to the same extent as an acceleration fuel-cut. During the aging procedure, exotherms were observed at the fuel-cut and the intensity of these exotherms was increasing with the length of aging time. The growing exotherms could be explained by the decomposition of HC into C and H2 and their subsequent oxidation at lean conditions. Also, the fuel-cut-off temperature measurements demonstrated that the magnitude of those exotherms was related to the total number as opposed to the total length of the fuel-cut. Copyright © 2014 SAE International.

A solid introduction to mathematical modeling for a range of chemical engineering applications, covering model formulation, simplification and validation. It explains how to describe a physical/chemical reality in mathematical language and how to select the type and degree of sophistication for a model. Model reduction and approximation methods are presented, including dimensional analysis, time constant analysis and asymptotic methods. An overview of solution methods for typical classes of models is given. As final steps in model building, parameter estimation and model validation and assessment are discussed. The reader is given hands-on experience of formulating new models, reducing the models and validating the models. The authors assume the knowledge of basic chemical engineering, in particular transport phenomena, as well as basic mathematics, statistics and programming. The accompanying problems, tutorials, and projects include model formulation at different levels, analysis, parameter estimation and numerical solution.

Many phenomena in engineering are very complex and we do not have sufficient knowledge at the moment to develop a model from first principles; instead, we have to rely on empirical correlations. Today most process development is done using empirical or semi-empirical models. These models are usually accurate and very useful. The drawback is that they are only valid for specific equipment within an experimental domain where the parameters are determined. In developing a correlation, we need first to identify all the variables that may have an influence on it. There are different approaches to finding important variables. One approach is to formulate the governing equations even if we do not have sufficient knowledge or computer resources to solve the equations. These equations and the corresponding boundary conditions provide information about which variables are important in formulating an empirical correlation. A second approach, used by experienced engineers, is to list all variables that are believed to be important. The final correlation is then obtained by experimenting and model fitting using experimental design to obtain reliable results and to minimize correlations between the parameters in the model.

In this chapter, kinetic models for ammonia SCR over Cu-zeolites are described. Both global and detailed models are presented and both commercial materials as well as model samples are used. In the SCR system, several reactions are important in order to describe the mechanism and these reactions are discussed below.

Modeling and flow reactor experiments were used to study the kinetics of NO, storage/release on a Pt/BaO/Al2O3 model catalyst. The mechanism for this concept can be divided into four steps: (i) NO to NO2 oxidation on Pt, (ii) NO2 storage on BaO, (iii) NO, release, and (iv) NO, reduction to N2. In this paper, we have focused on the first three steps. From the NO oxidation study on Pt/Al2O3 compared to Pt/BaO/Al2O3, we observed that the presence of BaO decreases the formation of NO2. To test the importance of this step for effective storage, experiments were performed with a Pt/Al2O3 catalyst placed before the Pt/BaO/Al2O3 catalyst. This resulted in increased NO, storage for the combined system compared to the Pt/BaO/Al2O3 case. To resolve the second and third steps, an experimental investigation of NOx storage/release on BaO/Al2O3 was performed using only NO2 and N2 in the gas feed. We propose a kinetic model, which first includes adsorption of NO2, which oxidizes the surface, followed by nitrate formation. Finally, NO3-BaO-NO2, i.e., Ba(NO3)2, is formed. By using the kinetic parameters from the NO oxidation on Pt/BaO/Al2O3 and the NO, storage on BaO/Al2O3, a kinetic model was constructed to describe NO, storage/release experiments on Pt/BaO/Al2O3. However, the rate for NO, release was increased when Pt was present, and the kinetic model could not accurately describe this phenomenon. Therefore, the mechanism was modified by including a reversible surface spillover step of NO2 between Pt sites and BaO sites. Further, experiments with NO2 exposure followed by a temperature ramp with NO/N2 showed that the desorption behaviors from the BaO/Al2O3 and Pt/BaO/Al2O3 were significantly different, which further supports the spillover mechanism. Finally, the models describing NO, storage on BaO/Al2O3 and on Pt/BaO/Al2O3 were successfully validated with independent experiments.

(2001). Gender mainstreaming in practice: The United Nations transitional assistance group in Namibia. International Peacekeeping: Vol. 8, Wonen and International Peacekeeping, pp. 97-110.

The storage of NOx under lean conditions in model NOx storage catalysts as well as the deactivation by sulphur have been studied. We find that NO2 plays an important role in the storage mechanism as an oxidising agent. Two different mechanisms for this are discussed: the formation of surface peroxides and the oxidation of nitrites to nitrates, FTIR studies show that NOx is stored as surface nitrates, The sulphur deactivation is found to be more severe when SO2 is added during the rich phase than when SO2 is added during the lean period. FTIR shows the formation of bulk sulphates both under lean and rich conditions.

Since the Beijing Conference in 1995, mainstreaming a gender perspective in the entire work of the United Nations has been a priority. This article presents a picture of the contemporary situation concerning the mainstreaming of a gender perspective in multidimensional peacekeeping operations. The main focus concerns female participation in the field which, historically, has been very low. Research indicates that more job opportunities for women exist in operations which contain a large civilian component, but that the military and police components remain mainly male. The article also argues that human rights and humanitarian assistance are two examples of areas of multidimensional peacekeeping operations where it is vital to consider the different needs of men and women.

The mechanisms for storing of NOx in platinum-barium-alumina catalysts during lean-rich transients are investigated. Oxidation of NO to NO2 is found to be an important step. NO2 is found to be important for oxidation of the catalyst or of nitrites to form nitrates. NOx is then stored in the form of surface nitrates. FTIR studies show no formation of bulk nitrates in these experiments.

Laboratory tests and kinetic modeling were carried out in order to provide kinetic input data to a systematic investigation of the mechanism of nitrogen oxides (NO,) storage in catalysts used for lean-burn engines. In particular, we present a kinetic model of the NO oxidation to NO2 over a Pt/Al2O3 model catalyst for the temperature range 250-450 degrees C. Since the oxygen behavior at atmospheric pressure is critical for such a model, we have also studied the adsorption/desorption of oxygen by temperature-programmed desorption (TPD) experiments. The experiments show that oxygen starts to desorb at about 300 degrees C. Furthermore, the NO oxidation was studied in a temperature ramp with NO and oxygen in the gas feed. The data from this experiment and the above-determined values for the oxygen adsorption/desorption were used to construct a kinetic model for the NO oxidation. Finally, the model was validated with some transient experiments with either NO or NO2 and different oxygen concentrations in the gas feed. We found a good agreement between these experiments and the model.

The two inequivalent sides of InSb(211) have been studied by scanning tunneling microscopy (STM), angle-resolved photoelectron spectroscopy (ARPS) and low-energy electron diffraction (LEED). Despite identical sputtering–annealing preparations, the surface qualities are very different in the two cases. The (211)A surface has a high degree of disorder reflected by a poor (1×1) LEED pattern and a lack of well-defined surface-induced features in valence band ARPS. In STM, this surface shows small (211) terraces with a high density of steps. The In core level spectrum of (211)A suggests presence of a metallic component. In contrast, the (211)B surface is ordered, with large flat terraces, and shows a sharp (1×1) LEED pattern. The In and Sb core level spectra are well fitted with one surface shifted component and show no sign of metallic In. In the valence band spectra, three surface-induced bands are observed. A tentative explanation for the asymmetry between the A- and B-sides in terms of bonds on the ideal surface is proposed.

The InAs(001) 2 × 4 and 4 × 2 surfaces have been investigated by angle-resolved photoemission. The X 3 and X 5 points were found to be located 6.0 and 2.7 eV below the valence band maximum, respectively, and the dispersion of bulk bands along the Г-X direction in the bulk Brillouin zone were well described by a theoretical calculation. From angle-resolved valence band spectra measured along the high symmetry directions [110] and [110], three surface induced states were identified on both the InAs(001)4 × 2 and the InAs(001)2 × 4 surface.

To determine the promoting effect of Rh on the overall NOx storage and reduction (NSR) performance, the studies in the current work were directed toward investigating the storage and release ability over Rh NOx storage BaO-based catalysts compared to Pt. In terms of the metal surface dispersion and the ability of the noble metals to release oxygen at lower temperatures, the synthesized catalysts were characterized by means of dynamic CO chemisorption (RT) and N2O dissociation (RI - 773 K). The NOx storage capacity and the thermal stability of the NOx adsorbed species formed on the surface were analyzed via NOx storage tests and temperature programmed desorption (TPD) without and in the presence of CO2 and H2O. In addition, experiments with lean and rich cycling were conducted at 473,573 and 673 K. The results from the N2O dissociation experiments showed the superior ability of Rh/Al and Rh/Ba/Al catalysts compared to Pt toward O-2 release from the catalytic surface at lower temperatures. In this work, we show that the presence of Rh into the BaO/gamma-Al2O3 system has a considerable effect on the spill-over process of NOx to the precious metal, controlling the subsequent desorption of NOx to occur at lower temperatures in comparison with that of the Pt catalysts. It is suggested a mechanism of NOx desorption where the lower temperature of O-2 release from the surface of Rh catalysts could leave a significant number of noble metal sites accessible for adsorption. Thus this could facilitate the rate of spill-over of NOx from the storage site (the surface sites on gamma-Al2O3 and those on BaO) to the noble metal and their desorption at lower temperatures. The limited NOx storage ability of the Rh-based BaO/gamma-Al2O3 catalysts under lean-burn conditions was found to originate from both low NO oxidation activity and NOx reduction activity, while the main limiting factor for the low NSR performance of the Pt-based catalysts was the limited regeneration ability during rich period.

The valence and core electronic structure of the sputtered and annealed 1 × 1 periodic GaAs(311)A surface has been studied by angle-resolved photoelectron spectroscopy. Five surface bands are identified and their dispersions along high symmetry lines in the surface Brillouin zone are mapped out. While electron-counting indicates a metallic surface, the experiment show no evidence for partly occupied surface bands. Analysis of the core level spectra reveals one As and two Ga surface shifted components. The results are discussed in terms of surface geometry models.

The electronic structure of molecular-beam-epitaxy-grown InAs(1\ifmmode\bar\else\textasciimacron\fi{} 1\ifmmode\bar\else\textasciimacron\fi{} 1\ifmmode\bar\else\textasciimacron\fi{})2\ifmmode\times\else\texttimes\fi{}2 and InSb(1\ifmmode\bar\else\textasciimacron\fi{} 1\ifmmode\bar\else\textasciimacron\fi{} 1\ifmmode\bar\else\textasciimacron\fi{})2\ifmmode\times\else\texttimes\fi{}2 surfaces is investigated by angle-resolved photoelectron spectroscopy. Valence-band spectra, and dispersions of five surface-related structures, are presented. The qualitative similarities of data from the two surfaces indicate that they are very similar, with respect to atomic and electronic structure. Comparisons with other (111) surfaces support the identification of the surface-related structures. \textcopyright{} 1996 The American Physical Society.

Angle-resolved valence band photoelectron spectra are collected from 1 X 1 ordered overlayers on 12-saturated GaAs(001)-4 X 1, -c(2 X 8), and InAs(001)-c(8 X 2). A high-intensity dispersive surface state, located approximately 4.4 eV below the valence band maximum, is observed in each case. The state passes through an open lens in the projected bulk density of states and disperses symmetrically around the surface Brillouin zone edge. For all surfaces studied, the state is stronger when excited with the electric field polarized in the [110], as compared to the [110], azimuth. Since the state is independent of the termination of the initial surface, and since iodine bonds primarily to the outermost element, the state must result from delocalization of the electron states in the overlayer, and is not related to bonding with the substrate.

Surface sensitive high resolution core level spectroscopy has been applied to the molecular beam epitaxy grown InAs ( 1 1 1 )2 × 2 and InSb ( 1 1 1 )2 × 2 surfaces. For both systems the In 4d core level consists of one dominating component while the Group V core levels are deconvoluted into four components. This analysis is consistent with a surface model where the topmost layer consists entirely of arsenic or antimony. In this model, Group V atoms form trimers bound to Group V atoms in the first double layer, leaving a single Group V rest atom per unit cell.

The surface electronic structure of the In-rich InSb(100)4 X 1 surface has been studied by angle-resolved photoelectron spectroscopy. To determine the origin of different contributions in spectra, direct bulk interband transitions were first identified using a semi-empirical band structure calculation and assuming direct transitions into free electron-like final bands. Three surface-induced features were identified and their dispersions have been mapped along symmetry directions of the surface Brillouin zone.

The differential adsorption heats of oxygen and NO, as well as catalytic oxidation behavior during NO oxidation and NO2 dissociation reactions over supported Pt-catalysts, were investigated by microcalorimetric measurements. The average heat of adsorption (Delta H) of oxygen ranged from 310 kJ/mol at 200 degrees C to 289 kJ/mol at 400 degrees C. Over this temperature range formation of platinum oxides and coverage dependence caused variations in the apparent heat of adsorption. NO heat of adsorption from 50 to 150 degrees C was near constant with an average value of 202 kJ/mol over the temperature range.

Endochondral bone formation involves the dynamic interplay between the cells and their extracellular environment to facilitate the deposition of a calcified matrix. Numerous molecules are involved within this process, including collagens and non-collagenous proteins, and their post-translational modifications have been shown to effect their biomolecular interactions. Osteoadherin (OSAD), a keratin sulfate (KS)-substituted small leucine-rich proteoglycan has been isolated from mineralized tissues and is considered to be a mineralized tissue-specific protein. However, to date, information is limited concerning the dynamic expression and role of this proteoglycan during bone formation and the biomineralization process. The current study aimed to examine the dynamic expression of this protein throughout mouse metatarsal long bone development, from the cartilage anlagen (E15) to the fully formed bone (Adult). Using quantitative gene expression analysis we observed that OSAD was produced with the onset of mineralization and the formation of the ossification center. This finding was reflected in the localization studies, using both light and electron microscopy, and showed that initial OSAD localization was restricted to the endosteal surfaces of the diaphysis and forming metaphysis. Furthermore, we analyzed protein extracts, both mineral and non-mineral associated fractions, and showed that OSAD was substituted with varying patterns of glycosylation during bone development. Sequential enzymatic digestions of the non-mineral bound protein extracts demonstrated that OSAD lacked any KS chains throughout all development stages. Whereas, in the mineral bound fractions, with long bone maturation the substitution with KS became more apparent with development. Therefore, it can be concluded that different pools of OSAD are produced during endochondral bone formation and these may have specific roles in directing the mineralization process.

Background Mounting collective radiation doses from computed tomography (CT) implies an increased risk of radiation-induced cancer in exposed populations, especially in the young. Purpose To evaluate radiation dose and image quality at 80-kVp CT to diagnose acute pulmonary embolism (PE) compared with a previous study at 100 and 120 kVp with all other scanning parameters unchanged. Material and Methods A custom-made chest phantom with a 12 mg I/mL-syringe was scanned at 80/100/ 120 kVp to evaluate relative changes in computed tomographic dose index (CTDIvol), attenuation, image noise, and contrast-to-noise ratio (CNR). Fifty patients underwent 80 kVp 16-row detector CT at 100 ‘Quality reference’ mAs. A total of 350 mg I/kg were injected to compensate for increased CNR at 80 kVp, while 300 mg I/kg had been used at 100/120 kVp. CTDIvol, dose-length product (DLP), and estimated effective dose were evaluated including Monte Carlo simulations. Pulmonary artery attenuation and noise were measured and CNR calculated. Two radiologists evaluated subjective image quality using a four-grade scale. Results Switching from 120 to 80 kVp in the phantom study decreased radiation dose by 67% while attenuation and noise increased 1.6 and 2.0 times, respectively, and CNR decreased by 16%. Switching from 120 to 80 kVp in the patient studies decreased estimated effective dose from 4.0 to 1.2 mSv (70% decrease) in median while pulmonary artery attenuation and noise roughly doubled from 332 to 653 HU and from 22 to 49 HU, respectively, resulting in similar CNR (13 vs. 12). At 80 kVp all examinations were regarded as adequate (8%) or excellent (92%). Conclusion Switching from 120 to 80 kVp CT without increased mAs but slightly increased iodine dose may be of special benefit to diagnose PE in younger individuals with preserved renal function where the primary aim is to minimize radiation dose and reaching levels below that of scintigraphy.

The number of CT examinations giving a relatively high patient exposure is increasing. It is therefore important to optimize the imaging conditions at these investigations. Many steps have been taken to reduce the radiation doses in CT examinations. Currently much work is related to iterative image reconstruction methods as alternative to the filtered back projection method. The aim of this work was to evaluate quality parameters in images from a CT (Philips Brilliance 64) equipped with the iterative reconstruction method iDose(4) using a Catphan 600 phantom with and without body simulating ring. CT scans using abdomen protocol were taken with various tube currents and tube voltage and keeping collimation and pitch unchanged for all scans. All collected data were reconstructed with different levels of iDose(4) (Level 2, 4, 6) and traditional filtered back projection. Image quality parameters were evaluated using AutoQA Lite (TM) (Version 2.3 2007 Iris QA, LLC). Results from the study shows that the iterative reconstruction method decreases the noise with 15-45% compared with filtered back projection depending on which level of iDose(4) is used. The percentage reduction in noise level is the same with and without body simulating ring. Low contrast was improved with iDose(4) and spatial resolution is only marginally affected by the method of reconstruction. However by reducing the image noise, the detectability can be improved. Our conclusion is that there is great potential to reduce the noise and thereby improve the image quality by using iterative reconstruction methods. This can also be used to lower radiation dose and maintain image quality or improve image quality. (Less)

It is shown that Ag/Al2O3 is a unique catalytic system for H2-assisted selective catalytic reduction of NOx by NH3 (NH3-SCR) with both Ag and alumina being necessary components of the catalyst. The ability of Ag/Al2O3 and pure Al2O3 to catalyse SCR of mixtures of NO and NO2 by ammonia is demonstrated, the surface species occurring discussed, and a "Fast SCR" -like mechanism of the process is proposed. The possibility of catalyst surface blocking by adsorbed NOx and the influence of hydrogen on desorption of NOx were evaluated by FTIR and DFT calculations. © 2011 Elsevier B.V.

Valence-band spectra from the sputtered and annealed InSb(1\ifmmode\bar\else\textasciimacron\fi{} 1\ifmmode\bar\else\textasciimacron\fi{} 1\ifmmode\bar\else\textasciimacron\fi{})3\ifmmode\times\else\texttimes\fi{}3 surface in normal emission and in the \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{} M\ifmmode\bar\else\textasciimacron\fi{}, \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{} M\ifmmode\bar\else\textasciimacron\fi{}', and \ensuremath{\Gamma}\ifmmode\bar\else\textasciimacron\fi{} K\ifmmode\bar\else\textasciimacron\fi{} azimuths have been measured. Some possible surface bands have been identified, among them one that clearly reflects the 3\ifmmode\times\else\texttimes\fi{}3 periodicity of the surface. Core-level spectra of Sb 4d and In 4d were deconvoluted revealing one surface-shifted component for Sb 4d and, surprisingly, no pronounced surface-shifted component for In 4d. Scanning tunneling microscopy images from this surface taken at different biases are presented. It is argued that the surface imaged at high bias is perturbed by the tip.

The electronic structure of the InAs( 111 )1 × 1 surface has been investigated by angle resolved photoelectron spectroscopy along the symmetry lines Γ K , Γ M , and Γ M ′ of the surface Brillouin zone. The bulk valence band structure was calculated using a combination of the linear augmented plane-wave method and the relativistic augmented plane-wave method. We have projected the theoretical bulk band structure onto the surface Brillouin zone to separate surface states from surface resonances. Two surface related structures, S1 and S2, have been observed and their Ei(k‖) dispersions are established. Both S1 and S2 show the symmetry of the 1 × 1 surface Brillouin zone, which is consistent with the observed 1 × 1 LEED pattern. We identify S1 as the As-derived dangling bond state, and S2 is associated with the backbonds connecting the As atoms in the surface layer with the underlying In layer.

Studies of colorectal cancer (CRC) have suggested different mechanisms of carcinogenesis in men and women, young and old patients, right- and left sided tumors, and sporadic and familial tumors. These differences might be reflected in morphology. CRCs from 1613 patients operated on in 2004–2006 in Sweden were histologically reviewed. Morphology was examined in relation to sex, age groups, location, and family history. Tumors in the right colon were larger, of higher stage, more often poorly differentiated, more mucin-producing, more often had a peritumoral lymphocytic infiltrate and a high level of tumor-infiltrating lymphocytes (TILs), and more seldom had an infiltrating margin than tumors in the left colon and rectum (p

The selective catalytic reduction of NO with NH3 over a Cu-BEA catalyst was studied after hydrothermal aging between 500 and 900 degrees C. The corresponding catalyst was characterized using XPS and XRD techniques in the aging interval of 500, 700 and 800 degrees C. No structural changes during the aging process were observed. However, the oxidation state of copper changed during aging and more Cu2+ was formed. We suggest that one of the deactivation mechanisms is the decrease of the Cu+ species. The NO oxidation and NH3 oxidation activity was decreased with increasing aging temperature. Further, we observed that the ammonia oxidation was decreased faster compared to the SCR reactions at low aging temperatures. The experiments from the calorimeter as well as from the ammonia TPD investigations indicate a trend towards more weakly bound ammonia with higher aging temperatures. From the results of the SCR experiments using different NO2/NOx ratios and ammonia oxidation experiments we suggest that most of the N2O is coming from side reactions of the SCR mechanism and not from reactions between NH3 and O-2 alone. Interestingly, we observe that after the 900 degrees C aging a quite large activity remained for the case with 75% NO2/NOx ratio. The N2O production shows a maximum at 200 degrees C, but increases again at higher temperatures. However, the N2O formed at low temperature is decreased after hydrothermal aging while the high temperature N2O is increased. We propose that the different reactions examined in this work do not all occur on the same type of sites, since we observe different aging trends for some of the reactions.

Objective:The experience of hope among cancer patients in palliative care is important information for healthcare providers, but research on the subject is sparse. The aim of this article was to explore how cancer patients admitted to palliative home care experienced the significance of hope and used hope during 6 weeks throughout the last phase of their life, and to assess their symptoms and hope status during 6 weeks throughout the last phase of their lives.Method:Eleven adult patients with cancer participated in 20 interviews and completed seven diaries. The participants were recruited from two palliative care units in the southeast of Sweden. The method used was Grounded Theory (GT), and analysis was based on the constant comparative method.Results:The core category, glimmering embers, was generated from four processes: (1) The creation of “convinced” hope, with a focus on positive events, formed in order to have something to look forward to; (2) The creation of “simulated hope,” including awareness of the lack of realism, but including attempts to believe in unrealistic reasons for hope; (3) The collection of and maintaining of moments of hope, expressing a wish to “seize the day” and hold on to moments of joy and pleasure; and (4) “Gradually extinct” hope, characterized by a lack of energy and a sense of time running out.Significance of results:The different processes of hope helped the patients to continue to live when they were close to death. Hope should be respected and understood by the professionals giving them support.

Purpose This article reports the social and psychological processes that 11 cancer patients receiving palliative home care used to keep their hope alive. Method The patients described their ways of dealing with hope in interviews and diaries, and it was from these accounts that the processes were extracted, using a grounded theory methodology. Results Two main processes emerged: maintaining life and preparing for death. When the patients focused on maintaining life, they tried to preserve its meaning and to communicate with others about life and death. They found it helpful to shift their focus and to involve fellow ‘travellers’ in their journey. To prepare for death was to take responsibility for the future and to see possibilities of living on even after death. Conclusion This paper revealed two parallel and interdependent processes used by patients in the palliative care phase to maintain hope and respond to living close to death.

Laboratory tests and kinetic modeling were carried out in order to provide kinetic input data to a systematic investigation of the mechanism of nitrogen oxides (NO,) storage in catalysts used for lean-burn engines. In particular, we present a kinetic model of the NO oxidation to NO2 over a Pt/Al2O3 model catalyst for the temperature range 250-450 degrees C. Since the oxygen behavior at atmospheric pressure is critical for such a model, we have also studied the adsorption/desorption of oxygen by temperature-programmed desorption (TPD) experiments. The experiments show that oxygen starts to desorb at about 300 degrees C. Furthermore, the NO oxidation was studied in a temperature ramp with NO and oxygen in the gas feed. The data from this experiment and the above-determined values for the oxygen adsorption/desorption were used to construct a kinetic model for the NO oxidation. Finally, the model was validated with some transient experiments with either NO or NO2 and different oxygen concentrations in the gas feed. We found a good agreement between these experiments and the model.

Today a high degree of "false" appendicitis diagnoses are occurring. In this study, a screening experiment of biomarkers of two different kinds of appendicitis, gangrenous and phlegmonous, were conducted with CE and CEC coupled to MS. Plasma samples were obtained from patients pre- and post-surgery. A large amount of data was generated to be able to compare them, and chemometrics tools were utilized to visualize the differences. Indicative patterns were found for both pre- and post-surgery of the two types of inflammation as well as between them. The divergences were traced back to the MS peaks obtained in the CE- and CEC-MS setups as possible biomarkers for the two forms of appendicitis.

The cell cycle checkpoint kinase 2 (CHEK2) 1100delC variant has recently been identified at high frequency in families with both breast and colorectal cancer, suggesting the possible role of this variant in colorectal cancer predisposition.To evaluate the role of CHEK2 ll00delC among Swedish colorectal cancer patients, the variant frequency was determined in 174 selected familial cases, 644 unselected cases and 760 controls, as well as in l8 families used in the genome-wide linkage analysis, where weak linkage was seen for the region harboring the CHEK2 gene.CHEK2 l100delC was found in 1.15% of familial and in 0.93% of unselected cases, compared to 0.66% of controls, showing no significant difference between groups. One out of 45 familial cases with a family history of breast cancer was shown to be a carrier. The variant was not identified in the 18 families included in the linkage analysis.The CHEK2 1100delC was not significantly increased in Swedish colorectal cancer patients, however, in order to determine the role of the variant in colorectal cancer families with the history of breast cancer a larger sample size is needed.

Dentine sialoprotein (DSP) represents 5–8% of all non-collagenous proteins present in the tooth, but, together with dentine phosphoprotein, has been shown to be vital for correct tooth formation. Recently, the existence of a highly glycosylated form of porcine DSP has been reported and it was shown to possess glycosaminoglycan (GAG) chains. The current investigation confirms that this is also the case for bovine DSP and has further characterized these carbohydrates. Dentine sialoprotein was purified from bovine dentine extracts by anion exchange chromatography and identified by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE), western blotting, and mass spectroscopy. An increase in molecular mass was observed, from 120 kDa to greater than 250 kDa, with a corresponding rise in anionic strength. Cellulose acetate electrophoresis and western blotting indicated the presence of chondroitin sulfate GAG chains within these dentine fractions. Further examination using sequential digestion with chondroitinase AC and N-glycosidase cleaved the samples first to 95 kDa and then to 80 kDa, respectively, confirming a high level of glycosylation. These results support the classification of bovine DSP as a proteoglycan, and that the carbohydrate substitutions may contribute to the functional properties of DSP.

Knowledge of the diagnostic work-up of colorectal cancer is a prerequisite to improve its quality. Family history is one of few known risk factors of the disease and it is therefore important to investigate to what extent this factor is used in routine management.Copies of records from all health-care suppliers visited during diagnostic work-up were requested for 227/235 (97%) patients with recently diagnosed colorectal cancer in the county of Västmanland during 1998-99. A first consultation was identified and records and all diagnostic measures related to the initial consultation were scrutinized. A family history of colorectal cancer was known for 179 patients.Most of the patients, 107 (66%) colon and 57 (86%) rectal cancer patients, had consulted with a general practitioner. The median diagnostic work-up time was 42 days (IQ 12-110) for colon and 23 days (IQ 0-49) for rectal cancer. A double-contrast barium enema was the most commonly used diagnostic method for colon cancer. Family history was documented at the first consultation in 2/179 (1%) cases. In patients with right-sided cancer, median diagnostic work-up time was 53 days in patients with a positive result of faecal occult blood test (FOBT) as compared with 448 in patients with a negative result (P0.01).Primary care is the key actor in diagnosing rectal cancer. The restricted capacity for X-ray is one of the main obstacles in detection of colon cancer. Family history is rarely documented during diagnostic work-up of colorectal cancer. The benefit of using FOBT in symptomatic patients is questioned.

Hereditary nonpolyposis colorectal cancer (HNPCC) and familial adenomatosis polyposis (FAP) are well-known high-risk cancer syndromes. Hereditary colorectal cancer (HCRC) with at least three relatives with colorectal cancer and a dominant pattern of inheritance but with no specifications for age at onset and two close relatives with colorectal cancer (TCR) are other forms of familial clustering known to carry an increased risk of the disease. The frequency of the total burden of familial colorectal cancer is not well known. We therefore investigated the family history of 400/411 (97%) eligible patients with recently diagnosed colorectal cancer in Västmanland county, Sweden, during a 3-year period. Records or death certificates confirmed the diagnoses of relatives. Five patients (1.2%, 95% CI 0.15-2.2) were diagnosed as having HNPCC, eight (1.9%, 95% CI 0.6-3.2) as having HCRC and thirty-four (8.3%, 95% CI 5.6-11.0) were identified as having TCR. In total, 47 patients (11.4%, 95% CI 8.3-14.5) were found to have a contributing familial background. The implication is thus that every ninth patient with colorectal cancer represents a highly or intermediately increased risk of the disease among relatives. We conclude that the low frequency of individuals identified by family history alone makes the establishment of surveillance programs feasible.