Global L∞L^\infty-estimate for general quasilinear elliptic equations in arbitrary domains of RN\mathbb{R}^N

In this paper our main goal is to present a new global $L^\infty$-estimate for a general class of quasilinear elliptic equations of the form $$-div \mathcal{A}(x,u,\nabla u)=\mathcal{B}(x,u,\nabla u)$$ under minimal structure conditions on the functions $\mathcal{A}$ and $\mathcal{B}$, and in arbitrary domains of $\mathbb{R}^N$. The main focus and the novelty of the paper is to prove $L^\infty$-estimate of the form $$|u|_{\infty, \Omega}\le C \Phi(|u|_{\beta,\Omega})$$ where $\Phi: \mathbb{R}^+\to \mathbb{R}^+$ is a data independent function with $\lim_{s\to 0^+}\Phi(s)=0$

Elliptic pp-Laplacian systems with nonlinear boundary condition

In this paper we study quasilinear elliptic systems given by \begin{equation*} \begin{aligned} -\Delta_{p_1}u_1 & =-|u_1|^{p_1-2}u_1 \quad && \text{in } \Omega,\newline -\Delta_{p_2}u_2 & =-|u_2|^{p_2-2}u_2 \quad && \text{in } \Omega,\newline |\nabla u_1|^{p_1-2}\nabla u_1 \cdot \nu &=g_1(x,u_1,u_2) && \text{on } \partial\Omega,\newline |\nabla u_2|^{p_2-2}\nabla u_2 \cdot \nu &=g_2(x,u_1,u_2) && \text{on } \partial\Omega, \end{aligned} \end{equation*} where $\nu(x)$ is the outer unit normal of $\Omega$ at $x \in \partial\Omega$, $\Delta_{p_i}$ denotes the $p_i$-Laplacian and $g_i\colon \partial\Omega \times\mathbb{R}\times\mathbb{R}\to\mathbb{R}$ are Carath\'{e}odory functions that satisfy general growth and structure conditions for $i=1,2$. In the first part we prove the existence of a positive minimal and a negative maximal solution based on an appropriate construction of sub- and supersolution along with a certain behavior of $g_i$ near zero related to the first eigenvalue of the $p_i$-Laplacian with Steklov boundary condition. The second part is related to the existence of a third nontrivial solution by imposing a variational structure, that is, $(g_1,g_2)=\nabla g$ with a smooth function $(s_1,s_2)\mapsto g(x,s_1,s_2)$. By using the variational characterization of the second eigenvalue of the Steklov eigenvalue problem for the $p_i$-Laplacian together with the properties of the related truncated energy functionals, which are in general nonsmooth, we show the existence of a nontrivial solution whose components lie between the components of the positive minimal and the negative maximal solution

EXISTENCE OF EXTREMAL PERIODIC SOLUTIONS FOR QUASILINEAR PARABOLIC EQUATIONS

Abstract. In this paper we consider a quasilinear parabolic equation in a bounded domain under periodic Dirichlet boundary conditions. Our main goal is to prove the existence of extremal solutions among all solutions lying in a sector formed by appropriately defined upper and lower solutions. The main tools used in the proof of our result are recently obtained abstract results on nonlinear evolution equations, comparison and truncation techniques and suitably constructed special testfunction

A New Fiducial Marker for Gated Radiotherapy in the Lung – A Feasibility Study of Bronchoscopy Based Insertion and Removal in Göttingen Mini-Pig

To develop a new prototype fiducial marker (LS-1) that may be used for gated radiotherapy in the lung.  One LS-1 marker was inserted in the lung of each animal under sedation. Animals were kept under observation  for four weeks after insertion. After the observation period the marker was removed. Animals were  CT scanned after insertion and before removal of the LS-1 marker. After the last CT scan animals were  euthanized and lungs excised for pathology. The LS-1 marker was successfully inserted in all fourteen animals. Thirteen of fourteen LS-1 marker’s  were in situ after four weeks. Two cases of pneumothorax were seen in connection with insertion. The LS-1  marker could only be successfully removed from eleven of thirteen animals. Damage to the lung was mainly  local close to the LS-1 marker insertion site. The LS-1 marker has the potential to be a fiducial marker suitable for gated external beam radiotherapy in  the lung. The method still needs some refinement prior to application in humans.

Sex-based differences in clinical and angiographic outcomes in patients with ST-elevation myocardial infarction treated with concomitant use of glycoprotein IIb/IIIa inhibitors

Background: The widespread use of primary coronary intervention (PCI) has significantly improved the prognosis of men presenting with acute coronary syndromes, but the cardiovascular event rate among women has either levelled off or increased. The purpose of the present prospective study was to compare the clinical outcome of women and men presenting with ST-elevation myocardial infarction (STEMI) undergoing primary PCI with concomitant usage of GP IIb/IIIa inhibitors. Methods: Between January 2006 and December 2007, 297 consecutive patients presenting with STEMI were prospectively included in this single center investigation. Overall, 82 (27.6%) women and 215 (72.4%) men were treated by PCI with additional bare metal stent implantation and a GP IIb/IIIa inhibitor. Results: Women were significantly older (65 ± 10 vs 60 ± 12 years, p = 0.04), presented with a smaller reference luminal diameter (2.83 ± 0.51 vs 2.94 ± 0.43, p = 0.03) and had a higher prevalence of hypertension (68% vs 53%, p = 0.025) and obesity (30% vs 18%, p = 0.03). The incidence of major adverse cardiac events (MACE, defined as death, re-myocardial infarction, target lesion revascularization and coronary artery bypass graft) during long-term follow-up was similar in women and men (20% vs 26%, p = 0.29). Age, C-reactive protein, platelet count and cardiogenic shock were identified as independent predictors for MACE, whereas gender was not predictive. Conclusions: In this study, female gender did not emerge as an independent predictor for MACE, but women presenting with STEMI had a higher cardiovascular risk profile; this emphasizes the need for a more extensive therapeutic strategy. Combination therapy with primary PCI and GP IIb/IIIa inhibitors might mitigate gender-related differences in clinical outcomes. (Cardiol J 2010; 17, 6: 580–586

Comparison of an interactive with a didactic educational intervention for improving the evidence-based practice knowledge of occupational therapists in the public health sector in South Africa: a randomised controlled trial

Background: Despite efforts to identify effective interventions to implement evidence-based practice (EBP), uncertainty remains. Few existing studies involve occupational therapists or resource-constrained contexts. This study aimed to determine whether an interactive educational intervention (IE) was more effective than a didactic educational intervention (DE) in improving EBP knowledge, attitudes and behaviour at 12 weeks. Methods: A matched pairs design, randomised controlled trial was conducted in the Western Cape of South Africa. Occupational therapists employed by the Department of Health were randomised using matched-pair stratification by type (clinician or manager) and knowledge score. Allocation to an IE or a DE was by coin-tossing. A self-report questionnaire (measuring objective knowledge and subjective attitudes) and audit checklist (measuring objective behaviour) were completed at baseline and 12 weeks. The primary outcome was EBP knowledge at 12 weeks while secondary outcomes were attitudes and behaviour at 12 weeks. Data collection occurred at participants’ places of employment. Audit raters were blinded, but participants and the provider could not be blinded. Results: Twenty-one of 28 pairs reported outcomes, but due to incomplete data for two participants, 19 pairs were included in the analysis. There was a median increase of 1.0 points (95% CI = -4.0, 1.0) in the IE for the primary outcome (knowledge) compared with the DE, but this difference was not significant (P = 0.098). There were no significant differences on any of the attitude subscale scores. The median 12-week audit score was 8.6 points higher in the IE (95% CI = -7.7, 27.0) but this was not significant (P = 0.196). Within-group analyses showed significant increases in knowledge in both groups (IE: T = 4.0, P <0.001; DE: T = 12.0, P = 0.002) but no significant differences in attitudes or behaviour. Conclusions: The results suggest that the interventions had similar outcomes at 12 weeks and that the interactive component had little additional effect

Impairment of chondrocyte biosynthetic activity by exposure to 3-tesla high-field magnetic resonance imaging is temporary

The influence of magnetic resonance imaging (MRI) devices at high field strengths on living tissues is unknown. We investigated the effects of a 3-tesla electromagnetic field (EMF) on the biosynthetic activity of bovine articular cartilage. Bovine articular cartilage was obtained from juvenile and adult animals. Whole joints or cartilage explants were subjected to a pulsed 3-tesla EMF; controls were left unexposed. Synthesis of sulfated glycosaminoglycans (sGAGs) was measured by using [(35)S]sulfate incorporation; mRNA encoding the cartilage markers aggrecan and type II collagen, as well as IL-1β, were analyzed by RT–PCR. Furthermore, effects of the 3-tesla EMF were determined over the course of time directly after exposure (day 0) and at days 3 and 6. In addition, the influence of a 1.5-tesla EMF on cartilage sGAG synthesis was evaluated. Chondrocyte cell death was assessed by staining with Annexin V and TdT-mediated dUTP nick end labelling (TUNEL). Exposure to the EMF resulted in a significant decrease in cartilage macromolecule synthesis. Gene expression of both aggrecan and IL-1β, but not of collagen type II, was reduced in comparison with controls. Staining with Annexin V and TUNEL revealed no evidence of cell death. Interestingly, chondrocytes regained their biosynthetic activity within 3 days after exposure, as shown by proteoglycan synthesis rate and mRNA expression levels. Cartilage samples exposed to a 1.5-tesla EMF remained unaffected. Although MRI devices with a field strength of more than 1.5 T provide a better signal-to-noise ratio and thereby higher spatial resolution, their high field strength impairs the biosynthetic activity of articular chondrocytes in vitro. Although this decrease in biosynthetic activity seems to be transient, articular cartilage exposed to high-energy EMF may become vulnerable to damage

Expert agreement confirms that negative changes in hand and foot radiographs are a surrogate for repair in patients with rheumatoid arthritis

The objective of the present study was to test the hypothesis that experts recognize repair of erosions and, if so, to determine which, if any, morphologic features permitted them to recognize the repair. We also tested whether scoring by a standard method detected repair. Seven experienced readers of radiographs in rheumatoid arthritis were presented with 64 sets of single joints-of-interest at two time points, randomized and blinded for the correct sequence. The readers assessed which joint was better, and recorded whether any of six specific features were seen. Two independent readers, experienced in scoring by the van der Heijde-modified Sharp method who were not on the expert panel, then scored the complete films that included the joint-of-interest. The panel agreed very well on which of two joints was better, and, even though they did not know the true sequence, the panel accurately assigned a sequence slightly better than chance alone (58%) but worse than their agreement on which image was 'better or worse' (78%). The readers therefore indirectly assigned repair by choosing the second film as the best. Putative repair features were seen in cases of both repair and progression, and were not discriminatory. Similar results were obtained when the experts were presented with the entire hand or foot containing the joint-of-interest. In the third repair exercise, two independent readers who scored whole hands and feet using a standard method found a mean negative score in 22/60 joints-of-interest. All 22 joints were also scored as repair by the panel. Repair was detected reliably by a majority of the panel on viewing paired images based on a better/worse decision and assigning sequence in a set of images that were blinded for sequence by an independent project manager. In this test set of images, repair was manifested by a reduction in the size of erosion in many cases. Size was one feature that aided the experts to detect repair but cannot be the only one; the experts had to find other features to determine whether a smaller erosion was the first in a sequence of radiographs in a patient with progressive damage or was the second film in a patient exhibiting repair. The change in size of erosion was also picked up by independent readers applying the van der Heijde-modified Sharp scoring method and was reflected in their scores