Search

In the original publication [...]

Experiments with changes in motion geometry can provide valuable data for engineering and development purposes, allowing a better understanding of the influence of tribological factors on the performance and service life of joints. The presented subject article focused on the experimental investigation of the influence of the geometry of the movement of the friction process on the change in the tribological properties of 30CrNiMo8 steel. The friction process was carried out without the use of a lubricant in contact with a steel ball of G40 material with a diameter of 4.76 mm. The steel ball performed two types of movement on the surface of the experimental material. The first method used was ball on disc, in which the ball moved reciprocally in an oval direction at an angle of 180° on a circumferential length of 35 mm at a speed of 5 mm/s. The second method consists of the same input parameters of the measurement, with the difference that the path along which the ball moved had a linear character. The load during the experiment was set at a constant value of 50 N with 1000 repetitions. The results show that with the ball on disc method, there was an increase in wear by 147% compared to the linear test method, which was approximately a coefficient of increase in wear of 2.468. EDS analysis pointed to the occurrence of oxidative wear that affected the resulting COF values, which were lower by 8% when using the ball on disc method due to a more uniform distribution of O and C on the surface of the friction groove where these elements acted as solid microlubricants. With the ball on disc method, defects in the form of microcracks occurred, which affected the reduction in the values of the depth of the affected area of microhardness.

Heart failure remains a major global burden regarding patients’ morbidity and mortality and health system organization, logistics, and costs. Despite continual advances in pharmacological and resynchronization device therapy, it is currently well accepted that heart transplantation and mechanical circulatory support represent a cornerstone in the management of advanced forms of this disease, with the latter becoming an increasingly accepted treatment modality due to the ongoing shortage of available donor hearts in an ever-increasing pool of patients. Mechanical circulatory support strategies have seen tremendous advances in recent years, especially in terms of pump technology improvements, indication for use, surgical techniques for device implantation, exchange and explantation, and postoperative patient management, but not in the field of treatment of critically ill patients and those undergoing cardiac arrest. This contemporary review aims to summarize the collected knowledge of this topic with an emphasis on complications in patients with left ventricular assist devices, their treatment, and establishing a clear-cut algorithm and the latest recommendations regarding out-of-hospital or emergency department management of cardiac arrest in this patient population.

This article presents the properties of a Ti coating (angle of grain growth, thickness of the deposited layer, adhesion, and roughness of the deposited layer) deposited on the inner surface of a steel tube. The Ti coating was deposited using the EB PVD (electron beam physical vapor deposition) method. The areas in which the measurements were carried out are defined by the height of the measured area under the target (from 305 to 425 mm) and the radius of the tube (from 100 to 140 mm). The measurements showed that the angle of grain growth is in an interval from 40 to 61°. The results of the statistical analysis demonstrate that the height of the measured area and the tube radius significantly impact the angle of grain growth and adhesion. On the other hand, the impact of the height of the measured area and the tube radius on the roughness of the applied coating was not confirmed. [ABSTRACT FROM AUTHOR]

(1) Background and Objectives: Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with increased morbidity and mortality both in the general population and heart failure patients. Inflammation may promote the initiation, maintenance and perpetuation of AF, but the impact of inflammatory molecular signaling on the association between AF and heart failure remains elusive. (2) Materials and Methods: In 111 patients with chronic stable heart failure, baseline values of conventional (IL-6 and hsCRP) and selected novel inflammatory biomarkers (IL-10, IL-6/IL-10 ratio, orosomucoid and endocan) were determined. Inflammatory biomarkers were compared with respect to the presenting cardiac rhythm. (3) Results: Patients aged below 75 years with AF had significantly higher values of IL-6 and IL-6/IL-10 ratio; IL-6 levels were a significant predictor of AF in both univariate (OR 1.175; 95%CI 1.013–1.363; p = 0.034) and multivariate logistic regression analysis when accounting for other inflammatory biomarkers (OR 1.327; 95% CI 1.068–1.650; p = 0.011). Conversely, there was no association between other novel inflammatory biomarkers and AF. (4) Conclusions: IL-6 levels and the IL-6/IL-10 ratio are associated with AF in patients with chronic stable heart failure under the age of 75 years, suggesting that inflammatory molecular signaling may play a role in the development of AF in the heart failure population. [ABSTRACT FROM AUTHOR]

Aspergillus infectious endocarditis (IE) is a rare cause of culture-negative endocarditis. The main risk factors are severe immunosuppression and prosthetic heart valve. We describe a case of Aspergillus fumigatus IE on a native mitral valve in a patient with autoimmune hepatitis in remission while on low dose corticosteroids. The case is unique due to the patients’ low initial risk for invasive fungal disease, its clinical presentation and successful management with emergency surgery and antifungal therapy. After literature review we have not found a similar case report. The patient presented with right-sided eyesight deterioration due to endophthalmitis. Vitrectomy was performed and Aspergillus fumigatus grew on culture. IE on a native mitral valve was confirmed with echocardiography. The patient developed signs of acute heart failure soon after hospital admission and was diagnosed with several septic emboli (kidney, spleen, thumb, right common femoral artery). He was initially treated with surgical valve replacement, dual antifungal therapy with liposomal amphotericin B (LAmB) and voriconazole and vitrectomy, including intravitreal amphotericin B application. Long-term triazole therapy was not possible due to hepatotoxicity. The patient was maintained on intermittent LAmB for 12 months and is without signs of recurrence ten months after therapy was discontinued. Aspergillus can cause invasive infection in patients with autoimmune hepatitis on low dose corticosteroids. Early diagnosis followed by emergency surgical valve replacement and systemic antifungal therapy can improve prognosis. Additional studies are needed to evaluate alternative methods and duration of antimicrobial therapy following Aspergillus IE.

The presented work deals with the investigation of mechanical tribological properties on Inconel 625 superalloy, which is welded on a 16Mo3 steel pipe. The wall thickness of the basic steel pipe was 7 mm, while the average thickness of the welded layer was 3.5 mm. The coating was made by the cold metal transfer (CMT) method. A supercritical bending of 180° was performed on the material welded in this way while cold. The mechanical properties evaluated were hardness, wear resistance, coefficient of friction (COF) and change in surface roughness for both materials. The UMT Tribolab laboratory equipment was used to measure COF and wear resistance by the Ball-on-flat method, which used a G40 steel pressure ball. The entire process took place at an elevated temperature of 500 °C. The measured results show that the materials after bending are reinforced by plastic deformation, which leads to an increase in hardness and also resistance to wear. Superalloy Inconel 625 shows approximately seven times higher rate of wear compared to steel 16Mo3 due to the creation of local oxidation areas that support the formation of abrasive wear and do not create a solid lubricant, as in the case of steel 16Mo3. Strain hardening leads to a reduction of possible wear on Inconel 625 superalloy as well as on 16Mo3 steel. In the case of the friction process, the places of supercritical bending of the structure showed the greatest resistance to wear compared to the non-deformed structure.

Anne Orholm Nielsen,1 Ole Hilberg,2,3 Jens Ulrik Stæhr Jensen,4 Steffen Helmer Kristensen,5 Jannie Christina Frølund,2 Pernille Kølholt Langkilde,6 Anders Løkke2,3 1Department of Medicine, Zealand University Hospital, Roskilde, Denmark; 2Department of Medicine, Hospital Little Belt, Vejle, Denmark; 3Department of Regional Health Research, University of Southern Denmark, Odense, Denmark; 4Department of Internal Medicine, Respiratory Medicine Section, Herlev and Gentofte Hospital, University Hospital of Copenhagen, Copenhagen, Denmark; 5Department of Pulmonary Medicine, Aalborg University Hospital, Aalborg, Denmark; 6Department of Medicine, Hospital Little Belt, Kolding, DenmarkCorrespondence: Anne Orholm NielsenDepartment of Medicine, Zealand University Hospital, Roskilde, DenmarkEmail anne_orholm@hotmail.comBackground: Inhaled corticosteroids (ICS) are widely used in the treatment of chronic obstructive pulmonary disease (COPD), but recent studies have raised doubts whether all COPD patients will benefit from ICS. This study evaluates in a real-life setting the effects of ICS withdrawal in patients with COPD.Methods: The study was a prospective intervention study following patients with COPD for 6 months after abrupt withdrawal of ICS. FEV1 (L), blood eosinophilic count (x10E9/L) and number of exacerbations were measured at baseline, 1, 3 and 6 months after ICS withdrawal.Results: Ninety-six patients (56 females (57.4%), mean age 70 years (51– 94 years)) with COPD were included in the study. Eleven patients were excluded during the study period (7 patients died, 4 patients withdrew their consent during the study period). During the 6 months, 51 patients (60%) had resumed treatment with ICS, of whom 34 patients (68%) experienced an exacerbation during follow-up. No significant decline in FEV1 was seen in this group between baseline and after 6 months (ΔFEV1 0.07 L, p = 0.09). In the remaining 34 patients (40%) without ICS after 6 months of follow-up, 15 patients (44.1%) experienced an exacerbation. No significant decline was seen in FEV1 at baseline and after 6 months (ΔFEV1 0.04 L, p = 0.28). There were no statistically significant differences between the two groups in age (70.5 vs 69.6 years, p = 0.53), nor between FEV1 at baseline (0.96 L vs 1.00 L, p = 0.63) or eosinophilic count (0.25 x10E9/L vs 0.17 x10E9/L, p = 0.07).Conclusion: Abrupt withdrawal of ICS was possible in some patients. However, more than half of the patients resumed ICS during follow-up. Based on results from our study we were not able to foresee – from neither history of exacerbations nor eosinophilic count – whom will be able to manage without ICS and who will resume treatment with ICS.Keywords: COPD, inhaled corticosteroids, withdrawal, real-life setting

Abstract Background Pocket-related complications following the implantation of cardiovascular implantable electronic devices primarily include pocket hematoma, infection, skin erosion or decubitus, device migration, and Twiddler's syndrome, with other pathologies such as nerve impairment or bone lesions being extremely rarely encountered. We report a case of a 20-year old asthenic, non-athlete female patient presenting with a device-generated fracture of the second rib several months after sub-muscular permanent pacemaker implantation due to repeated bilateral pre-pectoral pocket infections. Case presentation A 20-year old female patient was readmitted to our institution 9 months following sub-pectoral implantation of a permanent pacemaker, complaining of severe pocket-related pain, which arose spontaneously in the absence of direct trauma, intense physical activity or vigorous coughing, and was associated with normal day-to-day activity. To rule out a pacemaker re-infection, a native computed tomography and a positron emission tomography—computed tomography of the thorax were performed. Both modalities excluded an infection but showed a healing fracture and a focus of enhanced metabolic activity in the anterolateral part of the right second rib, indicating a non-traumatic or stress fracture of the bone. Consequently, a complete extraction of the pulse generator and both leads was performed and the smallest available single-chamber pulse generator with a single atrial electrode was implanted in the sub-fascial, pre-muscular pocket in the now recovered and uninfected left subclavicular region, alleviating patient’s severe pain symptoms and significantly enhancing her quality of life. Conclusions In the absence of direct trauma, intense physical activity or vigorous coughing, we assume that in this asthenic girl a normal day-to-day motion of the right shoulder has persistently forced the sub-muscularly placed pulse generator toward thoracic wall, putting increased repetitive pressure force on the underlying bones, finally causing a fatigue stress fracture of the second rib. In asthenic phenotype patients with small thorax and short subclavicular distance, a sub-muscular pacemaker implantation can potentially cause unique and unexpected pocket-related adverse events necessitating advanced diagnostics and timely treatment.