Showing papers by "Linköping University published in 2003"
29 Jun 2003
TL;DR: A method to estimate displacement fields from the polynomial expansion coefficients is derived and after a series of refinements leads to a robust algorithm that shows good results on the Yosemite sequence.
Abstract: This paper presents a novel two-frame motion estimation algorithm. The first step is to approximate each neighborhood of both frames by quadratic polynomials, which can be done efficiently using the polynomial expansion transform. From observing how an exact polynomial transforms under translation a method to estimate displacement fields from the polynomial expansion coefficients is derived and after a series of refinements leads to a robust algorithm. Evaluation on the Yosemite sequence shows good results.
2,338 citations
TL;DR: In this paper, the authors review the present understanding of film growth processes and their role in microstructural evolution as a function of deposition variables including temperature, the presence of reactive species, and the use of low-energy ion irradiation during growth.
Abstract: Atomic-scale control and manipulation of the microstructure of polycrystalline thin films during kinetically limited low-temperature deposition, crucial for a broad range of industrial applications, has been a leading goal of materials science during the past decades. Here, we review the present understanding of film growth processes—nucleation, coalescence, competitive grain growth, and recrystallization—and their role in microstructural evolution as a function of deposition variables including temperature, the presence of reactive species, and the use of low-energy ion irradiation during growth.
1,499 citations
01 Jan 2003-International Journal of Human-computer Studies \/ International Journal of Man-machine Studies
TL;DR: This paper follows the evolution of the Protege project through three distinct re-implementations, and describes the overall methodology, the design decisions, and the lessons learned over the duration of the project.
Abstract: The Protege project has come a long way since Mark Musen first built the Protege meta-tool for knowledge-based systems in 1987. The original tool was a small application, aimed at building knowledge-acquisition tools for a few specialized programs in medical planning. From this initial tool, the Protege system has evolved into a durable, extensible platform for knowledge-based systems development and research. The current version, Protege-2000, can be run on a variety of platforms, supports customized user-interface extensions, incorporates the Open Knowledge-Base Connectivity (OKBC) knowledge model, interacts with standard storage formats such as relational databases, XML, and RDF, and has been used by hundreds of individuals and research groups. In this paper, we follow the evolution of the Protege project through three distinct re-implementations. We describe our overall methodology, our design decisions, and the lessons we have learned over the duration of the project. We believe that our success is one of infrastructure: Protege is a flexible, well-supported, and robust development environment. Using Protege, developers and domain experts can easily build effective knowledge-based systems, and researchers can explore ideas in a variety of knowledge-based domains.
1,244 citations
TL;DR: In this paper, the design objective is to minimize a power function, which for the absence of body fluid forces is the dissipated power in the fluid, for the Stokes flow.
Abstract: We consider topology optimization of fluids in Stokes flow. The design objective is to minimize a power function, which for the absence of body fluid forces is the dissipated power in the fluid, su ...
798 citations
TL;DR: In this paper, the alternating copolymer with a C-60 derivative (PCBM) was used for solar cells with a power conversion efficiency of 2.2 % under simulated solar light.
Abstract: Solar cells prepared using the alternating copolymer shown in the Figure blended with a C-60 derivative (PCBM) are demonstrated to have a high performance, with a power conversion efficiency of 2.2 % under simulated solar light. The molecular weight of the polymer is low due to limited solubility, and films of the polymer exhibit red-shifted absorption.
715 citations
TL;DR: The effects of solvents on the morphology and sheet resistance in poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT-PSS) films were studied in this article.
710 citations
TL;DR: In this paper, a single crystalline and highly resistive wurtzite ZnO films were obtained from infrared (300-1200 cm−1) spectroscopic ellipsometry and Raman scattering studies.
Abstract: Infrared dielectric function spectra and phonon modes of high-quality, single crystalline, and highly resistive wurtzite ZnO films were obtained from infrared (300–1200 cm−1) spectroscopic ellipsometry and Raman scattering studies. The ZnO films were deposited by pulsed-laser deposition on c-plane sapphire substrates and investigated by high-resolution x-ray diffraction, high-resolution transmission electron microscopy, and Rutherford backscattering experiments. The crystal structure, phonon modes, and dielectric functions are compared to those obtained from a single-crystal ZnO bulk sample. The film ZnO phonon mode frequencies are highly consistent with those of the bulk material. A small redshift of the longitudinal optical phonon mode frequencies of the ZnO films with respect to the bulk material is observed. This is tentatively assigned to the existence of vacancy point defects within the films. Accurate long-wavelength dielectric constant limits of ZnO are obtained from the infrared ellipsometry anal...
580 citations
TL;DR: Several studies have shown that uncorrected hearing loss gives rise to poorer quality of life, related to isolation, reduced social activity, and a feeling of being excluded, leading to an increased prevalence of symptoms of depression, indicating the importance of early identification of hearing loss and offers of rehabilitative support.
Abstract: Hearing loss gives rise to a number of disabilities. Problems in recognizing speech, especially in difficult environments, give rise to the largest number of complaints. Other kinds of disabilities...
531 citations
TL;DR: X-ray photoelectron spectroscopy (XPS) has been used to characterize poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) (PEDT/PSS) as discussed by the authors.
Abstract: X-ray photoelectron spectroscopy (XPS) has been used to characterize poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) (PEDT/PSS), one of the most common electrically conducting organic pol ...
502 citations
TL;DR: Although statistical significance was not reached in the primary end point, the trial provides further support for IVIG as an efficacious adjunctive therapy in STSS.
Abstract: The efficacy and safety of high-dose intravenous polyspecific immunoglobulin G (IVIG) as adjunctive therapy in streptococcal toxic shock syndrome (STSS) were evaluated in a multicenter, randomized, double-blind, placebo-controlled trial. The trial was prematurely terminated because of slow patient recruitment, and results were obtained from 21 enrolled patients (10 IVIG recipients and 11 placebo recipients). The primary end point was mortality at 28 days, and a 3.6-fold higher mortality rate was found in the placebo group. A significant decrease in the sepsis-related organ failure assessment score at days 2 (P = .02) and 3 (P = .04) was noted in the IVIG group. Furthermore, a significant increase in plasma neutralizing activity against superantigens expressed by autologous isolates was noted in the IVIG group after treatment (P = .03). Although statistical significance was not reached in the primary end point, the trial provides further support for IVIG as an efficacious adjunctive therapy in STSS.
492 citations
TL;DR: Follow up after hospitalisation at a nurse-led heart failure clinic can improve survival and self-care behaviour in patients with heart failure as well as reduce the number of events, readmissions and days in hospital.
Abstract: Aim The aim of this trial was to prospectively evaluate the effect of follow-up at a nurse-led heart failure clinic on mortality, morbidity and self-care behaviour for patients hospitalised due to ...
TL;DR: The Bourgain, Brezis and Mironescu theorem on the asymptotic behaviour of the norm of the Sobolev-type embedding operator was studied in this paper.
TL;DR: In this paper, the authors present a dataset on CH4 flux rates totaling 12 measurement years at sites from Greenland, Iceland, Scandinavia and Siberia, and find that temperature and microbial substrate availability (expressed as the organic acid concentration in peat water) combined explain almost 100% of the variations in mean annual CH4 emissions.
Abstract: [1] Global wetlands are, at estimate ranging 115-237 Tg CH4/yr, the largest single atmospheric source of the greenhouse gas methane (CH4). We present a dataset on CH4 flux rates totaling 12 measurement years at sites from Greenland, Iceland, Scandinavia and Siberia. We find that temperature and microbial substrate availability (expressed as the organic acid concentration in peat water) combined explain almost 100% of the variations in mean annual CH4 emissions. The temperature sensitivity of the CH4 emissions shown suggests a feedback mechanism on climate change that could validate incorporation in further developments of global circulation models.
TL;DR: Some ways that gender can be and has been handled in studies of occupational health, as well as some of the consequences, are described and specific research practices that avoid errors are suggested.
Abstract: Background Both women's and men's occupational health problems merit scientific attention. Researchers need to consider the effect of gender on how occupational health issues are experienced, expressed, defined, and addressed. More serious consideration of gender-related factors will help identify risk factors for both women and men. Methods The authors, who come from a number of disciplines (ergonomics, epidemiology, public health, social medicine, community psychology, economics, sociology) pooled their critiques in order to arrive at the most common and significant problems faced by occupational health researchers who wish to consider gender appropriately. Results This paper describes some ways that gender can be and has been handled in studies of occupational health, as well as some of the consequences. The paper also suggests specific research practices that avoid errors. Obstacles to gender-sensitive practices are considered. Conclusions Although gender-sensitive practices may be difficult to operationalize in some cases, they enrich the scientific quality of research and should lead to better data and ultimately to well-targeted prevention programs. ⌐ 2003 Wiley-Liss, Inc.
TL;DR: A fluorometric DNA hybridization detection method based on non-covalent coupling of DNA to a water-soluble zwitterionic polythiophene derivative that offers a novel way to create DNA chips without using covalent attachment of the receptor or labelling of the analyte.
Abstract: Electronic polymers in aqueous media may offer bioelectronic detection of biospecific interactions. Here we report a fluorometric DNA hybridization detection method based on non-covalent coupling of DNA to a water-soluble zwitterionic polythiophene derivative. Introduction of a single-stranded oligonucleotide will induce a planar polymer and aggregation of the polymer chains, detected as a decrease of the intensity and a red-shift of the fluorescence. On addition of a complementary oligonucleotide, the intensity of the emitted light is increased and blue-shifted. The detection limit of this method is at present ∼10−11 moles. The method is highly sequence specific, and a single-nucleotide mismatch can be detected within five minutes without using any denaturation steps. The interaction with DNA and the optical phenomena persists when the polymer is deposited and patterned on a surface. This offers a novel way to create DNA chips without using covalent attachment of the receptor or labelling of the analyte.
06 Apr 2003
TL;DR: This work suggests and compares a Monte Carlo based method for positioning and a gradient search algorithm using a nonlinear least squares framework and has the feature of being easily extended to a dynamic framework where a motion model of the transmitter is included.
Abstract: The problem of position estimation from time difference of arrival (TDOA) measurements occurs in a range of applications from wireless communication networks to electronic warfare positioning. Correlation analysis of the transmitted signal to two receivers gives rise to one hyperbolic function. With more than two receivers, we can compute more hyperbolic functions, which ideally intersect in one unique point. With TDOA measurement uncertainty, we face a non-linear estimation problem. We suggest and compare a Monte Carlo based method for positioning and a gradient search algorithm using a nonlinear least squares framework. The former has the feature of being easily extended to a dynamic framework where a motion model of the transmitter is included. A small simulation study is presented.
TL;DR: A comprehensive, reliable and valid measure of the self-care behaviour of HF patients is needed to know how patients changed their self‐care behaviour as a result of a nurse‐led management programme.
Abstract: Background: Improvement of self-care behaviour is an aim of several non-pharmacological nurse-led management programmes for patients with heart failure. These programmes are often evaluated based on their effects on readmission, costs and quality of life. It is, however, also important to know how patients changed their self-care behaviour as a result of such a programme. Therefore a comprehensive, reliable and valid measure of the self-care behaviour of HF patients is needed. Objectives: To develop a scale measuring the behaviour that heart failure patients perform to maintain life, healthy functioning, and well-being. Method: The European Heart Failure Self-Care Behaviour Scale (EHFScBS) was developed in three phases: (1) concept analysis and first construction; (2) revision of items and response and scoring format; and (3) testing of the new scale for validity and reliability. Results: The European Heart Failure Self-Care Behaviour Scale is a 12-item, self-administered questionnaire that covers items concerning self-care behaviour of patients with heart failure. Face-validity and concurrent validity was established and the internal consistency of the scale was tested using pooled data of 442 patients from two centres in Sweden, three in the Netherlands and one in Italy. Cronbachs's alpha was 0.81. Conclusion: The instrument is a valid, reliable and practical scale to measure the self-reported self-care behaviour of heart failure patients. It is ready to use by investigators evaluating the outcome of heart failure management programmes that target changes in patients' self-care practices. (C) 2003 European Society of Cardiology. Published by Elsevier Science B.V. All rights reserved.
TL;DR: In this paper, the authors analyzed the phenomenon of corporate sustainability reporting in general and the use of CSR guidelines developed by the Global Reporting Initiative (GRI) in particular and found that companies produce CSRs mainly to seek organizational legitimacy, and that the main reason for use of the GRI guidelines is an expectation of increasing credibility of the CSR, but also that it provides a template for how to design a report.
Abstract: With empirical evidence from Swedish companies, this paper analyses the phenomenon of corporate sustainability reporting (CSR) in general and the use of CSR guidelines developed by the Global Reporting Initiative (GRI) in particular. The main questions at issue are why companies have chosen to use the GRI guidelines and how this has affected corporate social responsibility and environmental management. From interviews with all Swedish companies that use the guidelines, we have found that companies produce CSRs mainly to seek organizational legitimacy, and that the main reason for use of the GRI guidelines is an expectation of increasing credibility of the CSR, but also that it provides a template for how to design a report. Moreover, we have found that the CSR report and the GRI guidelines are of more help for internal than external communication at this stage of development. It could help corporations to learn about themselves and to see what has actually been done in the organization. In all, the GRI guidelines would have the potential for gaining visibility and control of the triple bottom line on a corporate level, but they are in need of further development, not least in relation to the issue of verification. Copyright © 2003 John Wiley & Sons, Ltd and ERP Environment.
University of Southern California1, International Agency for Research on Cancer2, Karolinska Institutet3, Fudan University4, University of Hawaii at Manoa5, University of Milan6, National and Kapodistrian University of Athens7, University of Tromsø8, Fred Hutchinson Cancer Research Center9, National Institutes of Health10, Mario Negri Institute for Pharmacological Research11, Linköping University12
TL;DR: Thyroid cancer risk was reduced in persons who had ever smoked and a reduced risk associated with alcohol was eliminated after adjustment for smoking, and caffeinated beverages did not alter thyroid cancer risk.
Abstract: Objective: To analyze the role of smoking, alcohol, coffee and tea in relation to thyroid cancer, we conducted a pooled analysis of 14 case–control studies conducted in the United States, Europe, and Asia. Methods: The sample consisted of 2725 thyroid cancer cases (2247 females, 478 males) and 4776 controls (3699 females, 1077 males). Conditional logistic regression with stratification on study, age at diagnosis, and gender was used to compute odds ratios and 95% confidence intervals. Results: Thyroid cancer risk was reduced in persons who had ever smoked. The relationship was more pronounced in current smokers (OR = 0.6, 95% CI = 0.6–0.7) than former smokers (OR = 0.9, 95% CI = 0.8–1.1). There were significant trends of reduced risk with greater duration and frequency of smoking. For consumption of wine and beer, there was a significant trend of decreasing thyroid cancer risk (p = 0.02) that was not maintained after adjustment for current smoking (p = 0.12). Thyroid cancer risk was not associated with consumption of coffee or tea. These findings were consistent in both gender-specific and histology-specific (papillary and follicular) analyses. Conclusions: Pooled analyses of these geographically diverse case–control data indicate a reduced thyroid cancer risk associated with current smoking. A reduced risk associated with alcohol was eliminated after adjustment for smoking, and caffeinated beverages did not alter thyroid cancer risk.
TL;DR: In this article, the authors present experiences from the standards implementation processes in Sweden and make comparisons between ISO 14000 and ISO 9000 systems, focusing on motives for implementation, perceived benefits and key implementation factors.
Abstract: ISO 14000 is based on the concept that better environmental performance can be achieved when environmental aspects are systematically identified and managed. Despite the growing interest in voluntary environmental management standards, little empirical information exists and only a few survey studies have been made. This paper contains an evaluation of results from a survey on ISO 14000 and ISO 9000 companies. The study presents experiences from the standards implementation processes in Sweden. It focuses on motives for implementation, perceived benefits and key implementation factors. Further, comparisons are made between ISO 14000 and ISO 9000 systems. Swedish companies mainly use the standard to demonstrate their commitment to environmental protection. Most benefits are also perceived in the improved relations with stakeholders and in marketing advantages. Since the standard requires companies to set their environmental policy and objectives themselves, the identification of environmental aspects was stated as most important and also as the factor requiring most effort. Organizations require their suppliers to implement ISO 9000 to a greater extent than ISO 14000.
01 Jan 2003
TL;DR: In this paper, an adaptive backstepping and nonlinear observer design method is proposed for nonlinear control problems in flight control and the results are presented in a general framework and can also be applied to other areas.
Abstract: In this thesis we study a number of nonlinear control problems motivated by their appearance in flight control. The results are presented in a general framework and can also be applied to other areas. The two main topics are backstepping and control allocation.Backstepping is a nonlinear control design method that provides an alternative to feedback linearization. Here, backstepping is used to derive robust linear control laws for two nonlinear systems, related to angle of attack control and flight path angle control, respectively. The resulting control laws require less modeling information than corresponding designs based on feedback linearization, and achieve global stability in cases where feedback linearization can only be performed locally. Further, a method for backstepping control of a rigid body is developed, based on a vector description of the dynamics. We also discuss how to augment an existing nonlinear controller to suppress constant input disturbances. Two methods, based on adaptive backstepping and nonlinear observer design, are proposed.Control allocation deals with actuator utilization for overactuated systems. In this thesis we pose the control allocation problem as a constrained least squares problem to account for actuator position and rate constraints. Efficient solvers based on active set methods are developed with similar complexity to existing, approximate, pseudoinverse methods. A method for dynamic control allocation is also proposed which enables a frequency dependent control distribution among the actuators to be designed. Further, the relationship between control allocation and linear quadratic control is investigated. It is shown that under certain circumstances, the two techniques give the same freedom in distributing the control effort among the actuators. An advantage of control allocation, however, is that since the actuator constraints are considered, the control capabilities of the actuator suite can be fully exploited.
TL;DR: In this article, an inverse scattering approach for computing n-peakon solutions of the Degasperis-Procesi equation (a modification of the Camassa-Holm (CH) shallow water equation) is presented.
Abstract: We present an inverse scattering approach for computing n-peakon solutions of the Degasperis-Procesi equation (a modification of the Camassa-Holm (CH) shallow water equation) The associated non-self-adjoint spectral problem is shown to be amenable to analysis using the isospectral deformations induced from the n-peakon solution, and the inverse problem is solved by a method generalizing the continued fraction solution of the peakon sector of the CH equation
05 Apr 2003
TL;DR: The key principles for the SHARK design include high efficiency stemmed from layout optimization, duality of gesturing and stylus tapping, scale and location independent writing, Zipf's law, and skill transfer from tapping to shorthand writing due to pattern consistency.
Abstract: We propose a method for computer-based speed writing, SHARK (shorthand aided rapid keyboarding), which augments stylus keyboarding with shorthand gesturing. SHARK defines a shorthand symbol for each word according to its movement pattern on an optimized stylus keyboard. The key principles for the SHARK design include high efficiency stemmed from layout optimization, duality of gesturing and stylus tapping, scale and location independent writing, Zipf's law, and skill transfer from tapping to shorthand writing due to pattern consistency. We developed a SHARK system based on a classic handwriting recognition algorithm. A user study demonstrated the feasibility of the SHARK method.
TL;DR: In this paper, the authors compared electrochemically prepared poly(3,4-ethylenedioxythiophene) (PEDT) poly(styrenesulfonate) (PSS), produced from acidic (PSSH) and basic (PSSNa) PSS, was characterized by cyclic voltammetry CV, UV−vis spectroscopy, in situ conductivity, and XPS analysis.
Abstract: Electrochemically prepared poly(3,4-ethylenedioxythiophene) (PEDT) poly(styrenesulfonate) (PSS), produced from acidic (PSSH) and basic (PSSNa) PSS, was characterized by cyclic voltammetry CV, UV−vis spectroscopy, in situ conductivity, and XPS spectroscopy and was compared with electrochemically prepared PEDT/tosylate and chemically prepared PEDT/PSS. CV analysis shows that the polymer synthesis is strongly affected by the nucleophilic character of the counteranion. Although CV and UV−vis spectroscopy show that the structure and degree of polymerization (oligomeric, ca. 10 EDT units) of the PEDT backbone is the same for all polymers, XPS is able to explain the different conductivity values for these materials (ranging from 1 S cm-1 for PEDT/PSSNa to 400−450 S cm-1 for PEDT/tosylate) based on doping level and composition. In particular, critical results are observed to be the ratios between sulfonate and thiophene units in the polymers: the higher the PEDT concentration, the higher the conductivity. XPS al...
TL;DR: In this paper, the electrochemical bandgaps for different soluble substituted polythiophenes have been measured by cyclic voltammetry and the effect of substituents on the oxidation/reduction potentials is discussed.
Abstract: The electrochemical bandgaps for different soluble substituted polythiophenes have been measured by cyclic voltammetry. The effect of substituents on the oxidation/reduction potentials is discussed. Bandgaps obtained by cyclic voltammetry have been found to be in general higher than optical bandgaps. Among regioregular polymers substituted with a phenyl group at position 3 of the thiophene ring, examples are found that give very symmetric voltammograms. Rationalization for this behaviour is discussed from a conformational point of view.
TL;DR: In this paper, it was shown that the lysomotropic detergent O-methyl-serine dodecylamide hydrochloride (MSDH) causes lysosomal rupture, enhanced intracellular ROS production, and apoptosis.
Abstract: Exposure of mammalian cells to oxidant stress causes early (iron catalysed) lysosomal rupture followed by apoptosis or necrosis. Enhanced intracellular production of reactive oxygen species (ROS), presumably of mitochondrial origin, is also observed when cells are exposed to nonoxidant pro-apoptotic agonists of cell death. We hypothesized that ROS generation in this latter case might promote the apoptotic cascade and could arise from effects of released lysosomal materials on mitochondria. Indeed, in intact cells (J774 macrophages, HeLa cells and AG1518 fibroblasts) the lysosomotropic detergent O-methyl-serine dodecylamide hydrochloride (MSDH) causes lysosomal rupture, enhanced intracellular ROS production, and apoptosis. Furthermore, in mixtures of rat liver lysosomes and mitochondria, selective rupture of lysosomes by MSDH promotes mitochondrial ROS production and cytochrome c release, whereas MSDH has no direct effect on ROS generation by purifed mitochondria. Intracellular lysosomal rupture is associated with the release of (among other constituents) cathepsins and activation of phospholipase A2 (PLA2). We find that addition of purified cathepsins B or D, or of PLA2, causes substantial increases in ROS generation by purified mitochondria. Furthermore, PLA2 - but not cathepsins B or D - causes rupture of semipurified lysosomes, suggesting an amplification mechanism. Thus, initiation of the apoptotic cascade by nonoxidant agonists may involve early release of lysosomal constituents (such as cathepsins B and D) and activation of PLA2, leading to enhanced mitochondrial oxidant production, further lysosomal rupture and, finally, mitochondrial cytochrome c release. Nonoxidant agonists of apoptosis may, thus, act through oxidant mechanisms.
TL;DR: The high irregularity of neural persistent activity during the delay period is likely to be a characteristic signature of recurrent prefrontal network dynamics underlying working memory.
Abstract: An important question in neuroscience is whether and how temporal patterns and fluctuations in neuronal spike trains contribute to information processing in the cortex. We have addressed this issue...
TL;DR: Results provide support for the idea that activation of the MAP kinase pathway, especially via BRAF and KRAS mutations, is of critical importance for the development of colorectal cancer.
Abstract: Colorectal cancer is a multi-step process characterized by a sequence of genetic alterations in cell growth regulatory genes, such as the adenomatous polyposis coli, KRAS, p53 and DCC genes. In the present study mutation analysis was performed with SSCA/direct sequencing of the hot-spot regions in exons 11 and 15 for the BRAF gene and exons 1-2 for the KRAS gene in 130 primary colorectal cancer tumors and correlated with clinico-pathological and mutational data. We also performed mutation analysis of the corresponding conserved regions in the ARAF and RAF-1 genes. Mutations in the BRAF and KRAS genes were found in 11.5 and 40% of the tumors, respectively. One germline exonic and nine germline intronic genetic variants were found in the ARAF and RAF-1 genes. All of the BRAF mutations were located in the kinase domain of the conserved region 3 in exon 15 of the BRAF gene. One novel somatic mutation was also identified in the BRAF gene. The majority of the BRAF mutations were found in colon compared with rectal tumors (P = 0.014). In agreement with others, a statistically significant correlation between BRAF mutations and microsatellite instability could be found. A negative correlation was also evident between mutations in the BRAF and KRAS genes, which supports earlier studies where somatic mutations in these genes are mutually exclusive. Collectively, our results provide support for the idea that activation of the MAP kinase pathway, especially via BRAF and KRAS mutations, is of critical importance for the development of colorectal cancer.
TL;DR: In this article, the structure and macroscopic properties of droplet free CrN films deposited by the recently developed high power pulsed magnetron sputtering (HIPIMS) technique are presented.
Abstract: Microstructure and macroscopic properties of droplet free CrN films deposited by the recently developed high power pulsed magnetron sputtering (HIPIMS) technique are presented. Magnetron glow discharges with peak power densities reaching 3000 W cm−2 were used to sputter Cr targets in both inert and reactive gas atmospheres. The flux arriving at the substrates consisted of neutrals and ions (approx. 70/30) of the sputtered metal and working gas atoms (Ar) with significantly elevated degree of ionization compared to conventional magnetron sputtering. The high-speed steel and stainless steel substrates were metal ion etched using a bias voltage of −1200 V prior to the deposition of CrN films. The film-to-substrate interfaces, observed by scanning transmission electron microscope cross-sections, were clean and contained no phases besides the film and substrate ones or recrystallized regions. CrN films were grown by reactive HIPIMS at floating potential reaching −160 V. Initial nucleation grains were large compared to conventional magnetron sputtered films, indicating a high adatom mobility in the present case. The films exhibited polycrystalline columnar growth morphology with evidence of renucleation. No intercolumnar voids were observed and the corrosion behavior of the film was superior to arc deposited CrNx. A high density of lattice defects was observed throughout the films due to the high floating potential. A residual compressive stress of 3 GPa and a hardness value of HK0.025=2600 were measured. A low friction coefficient of 0.4 and low wear rates against Al2O3 in these films are explained by the absence of droplets and voids known to contribute to extensive debris generation.
TL;DR: The diagnostic accuracy of the clinical examination and clinical reasoning process was superior to the sacroiliac joint pain provocation tests alone, and a specific clinicalexamination and reasoning process can differentiate between symptomatic and asymptomatic sac roiliac joints.
Abstract: Research suggests that clinical examination of the lumbar spine and pelvis is unable to predict the results of diagnostic injections used as reference standards. The purpose of this study was to assess the diagnostic accuracy of a clinical examination in identifying symptomatic and asymptomatic sacroiliac joints using double diagnostic injections as the reference standard. In a blinded concurrent criterion-related validity design study, 48 patients with chronic lumbopelvic pain referred for diagnostic spinal injection procedures were examined using a specific clinical examination and received diagnostic intraarticular sacroiliac joint injections. The centralisation and peripheralisation phenomena were used to identify possible discogenic pain and the results from provocation sacroiliac joint tests were used as part of the clinical reasoning process. Eleven patients had sacroiliac joint pain confirmed by double diagnostic injection. Ten of the 11 sacroiliac joint patients met clinical examination criteria for having sacroiliac joint pain. In the primary subset analysis of 34 patients, sensitivity, specificity and positive likelihood ratio (95% confidence intervals) of the clinical evaluation were 91% (62 to 98), 83% (68 to 96) and 6.97 (2.70 to 20.27) respectively. The diagnostic accuracy of the clinical examination and clinical reasoning process was superior to the sacroiliac joint pain provocation tests alone. A specific clinical examination and reasoning process can differentiate between symptomatic and asymptomatic sacroiliac joints. [Laslett M, Young SB, Aprill CN and McDonald B (2003): Diagnosing painful sacroiliac joints: A validity study of a McKenzie evaluation and sacroiliac provocation tests. Australian Journal of Physiotherapy 49: 89-97]