Non-HIV-related comorbidities and uncontrolled HIV replication are independent factors increasing the odds of hospitalization due to COVID-19 among HIV-positive patients in Poland.

PURPOSE: Immunocompromised patients are postulated to be at elevated risk of unfavorable outcomes of COVID-19. The exact effect of HIV infection on the course of COVID-19 remains to be elucidated. The aim of the study was to describe the epidemiological and clinical aspects of SARS-CoV-2 infection in HIV-infected individuals. METHODS: The HIV-positive patients who were diagnosed with SARS-CoV-2 infection were identified through thirteen specialist HIV clinics routinely following them due to HIV treatment. The data were collected between November 2020 and May 2021 through an on-line electronical case report form (SurveyMonkey®). The collected information included demographics, lifestyle, comorbidities, HIV care history, COVID-19 clinical course and treatment. Logistic regression models were used to identify factors associated with the odds of death or hospitalization due to COVID-19. RESULTS: One hundred and seventy-three patients with HIV-SARS-CoV-2 coinfection were included in the analysis. One hundred and sixty-one (93.1%) subjects had a symptomatic course of the disease. Thirty-nine (23.1%) of them were hospitalized, 23 (13.3%) necessitated oxygen therapy. Three (1.8%) patients required admission to the intensive care unit and 6 (3.5%) patients died. The presence of comorbidities and an HIV viral load of more than 50 copies/mL were linked to the increased odds of hospitalization (OR 3.24 [95% CI 1.27-8.28]) and OR 5.12 [95% CI 1.35-19.6], respectively). CONCLUSIONS: As depicted by our analyses, HIV-positive patients with comorbidities and/or uncontrolled HIV replication who are diagnosed with SARS-CoV-2 infection should be considered of high risk of poor COVID-19 outcome and followed up carefully.

Retrospective evaluation of an observational cohort by the Central and Eastern Europe Network Group shows a high frequency of potential drug-drug interactions among HIV-positive patients receiving treatment for coronavirus disease 2019 (COVID-19).

OBJECTIVES: The aim of this international multicentre study was to review potential drug-drug interactions (DDIs) for real-life coadministration of combination antiretroviral therapy (cART) and coronavirus disease 2019 (COVID-19)-specific medications. METHODS: The Euroguidelines in Central and Eastern Europe Network Group initiated a retrospective, observational cohort study of HIV-positive patients diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Data were collected through a standardized questionnaire and DDIs were identified using the University of Liverpool's interaction checker. RESULTS: In total, 524 (94.1% of 557) patients received cART at COVID-19 onset: 117 (22.3%) were female, and the median age was 42 (interquartile range 36-50) years. Only 115 (21.9%) patients were hospitalized, of whom 34 required oxygen therapy. The most frequent nucleoside reverse transcriptase inhibitor (NRTI) backbone was tenofovir disoproxil fumarate (TDF)/tenofovir alafenamide (TAF) with lamivudine or emtricitabine (XTC) (79.3%) along with an integrase strand transfer inhibitor (INSTI) (68.5%), nonnucleoside reverse transcriptase inhibitor (NNRTI) (17.7%), protease inhibitor (PI) (13.7%) or other (2.5%). In total, 148 (28.2%) patients received COVID-19-specific treatments: corticosteroids (15.7%), favipiravir (7.1%), remdesivir (3.1%), hydroxychloroquine (2.7%), tocilizumab (0.6%) and anakinra (0.2%). In total, 62 DDI episodes were identified in 58 patients (11.8% of the total cohort and 41.9% of the COVID-19-specific treatment group). The use of boosted PIs and elvitegravir accounted for 43 DDIs (29%), whereas NNRTIs were responsible for 14 DDIs (9.5%). CONCLUSIONS: In this analysis from the Central and Eastern European region on HIV-positive persons receiving COVID-19-specific treatment, it was found that potential DDIs were common. Although low-dose steroids are mainly used for COVID-19 treatment, comedication with boosted antiretrovirals seems to have the most frequent potential for DDIs. In addition, attention should be paid to NNRTI coadministration.

Study of the first clinical cases on monkeypox in Poland.

Monkeypox is a viral, zoonotic, emerging infectious disease that has become the most significant orthopoxviral infection among humans since the eradication of smallpox. It is endemic in Central and West Africa, and since May 2022 it has caused a multi-country outbreak in six continents. So far, no clinical cases of this disease have been observed in Poland. Monkeypox can be transmitted by any person, regardless of gender identity or sexual preferences, through direct contact with the secretion from skin lesions or through fomites contaminated with infectious material. Therefore, people infected with the monkeypox virus require isolation until the skin lesions heal completely and the scabs fall off, which is equivalent to the end of their infectivity. The paper presents a study of the first nine clinical cases of monkeypox in Poland, along with photographic documentation. All patients were young men, the vast majority of whom had contact with multiple sexual partners, and presented a higher prevalence of human immunodeficiency virus (HIV) infection than in the general population. The course of the disease was self-limited and no specific antiviral treatment was required by any of the patients. Nonetheless, there was a change in the route of transmission of the infection to sexual contact and an atypical clinical course of the disease, which resulted both in skin lesions initially appearing in the anogenital area, skin lesions occurring at various stages of development, and the appearance of skin lesions before the onset of general symptoms. In one of the patients, skin changes were not observed at all.

An aggressive course of pyoderma gangrenosum mimicking bacterial osteomyelitis after open reduction and internal fixation of a distal radius fracture with a titanium plate.

Pyoderma gangrenosum (PG) is a rare condition characterized by the development of aseptic, non-healing skin ulcers. Any skin trauma, such as a surgical incision, can trigger an outbreak of lesions. Our case and literature review show that a physician should consider PG in every event of a non-healing, aseptic wound after surgery. The treatment of PG requires collaboration within a multidisciplinary team and immunosuppressive therapy is the first line of treatment, while surgical interventions should be avoided in the active stage of PG.

Interobserver Agreement in Semi-Quantitative Scale-Based Interpretation of Chest Radiographs in COVID-19 Patients.

BACKGROUND The chest X-ray is the most available imaging modality enabling semi-quantitative evaluation of pulmonary involvement. Parametric evaluation of chest radiographs in patients with SARS-CoV-2 infection is crucial for triage and therapeutic management. The CXR Score (Brixia Score), SARI CXR Severity Scoring System, and Radiographic Assessment of Lung Edema (RALE), proposed to evaluate SARS-CoV-2 infiltration of the lungs, were analyzed for interobserver agreement. MATERIAL AND METHODS This study analyzed 200 chest X-rays from 200 consecutive patients with confirmed SARS-CoV-2 infection, hospitalized at the Central Clinical Hospital of the Ministry of the Interior and Administration in Warsaw. Radiographs were evaluated by 2 radiologists according to 3 scales: SARI, RALE, and CXR Score. RESULTS The overall interobserver agreement for SARI ratings was good (kappa=0.755; 95% CI, 0.817-0.694), for RALE scale assessments it was very good (kappa=0.818; 95% CI, 0.844-0.793), and for CXR scale assessments it was very good (kappa=0.844; 95% CI, 0.846-0.841). A moderate correlation was found between the radiological image assessed using each of the scales and the clinical condition of the patient in MEWS (Modified Early Warning Score) (r=0.425-0.591). CONCLUSIONS The analyzed scales are characterized by good or very good interobserver agreement of assessments of the extent of pulmonary infiltration. Since the CXR Score showed the strongest correlation with the clinical condition of the patient as expressed using the MEWS scale, it is the preferred scale for chest radiograph assessment of patients with COVID-19 in the light of data provided.

COVID-19 severity scoring systems in radiological imaging - a review.

The current reference standard to make a definitive diagnosis of SARS-CoV-2 infection is the reverse transcription- polymerase chain reaction assay (rt-PCR). However, radiological imaging plays a crucial role in evaluating the course of COVID-19 and in choosing proper management of infected patients. Chest X-ray (CXR) is generally considered not to be sensitive for the detection of pulmonary abnormalities in the early stage of the disease. However, in the emergency setting CXR can be a useful diagnostic tool for monitoring the rapid progression of lung involvement in COVID-19, especially in patients admitted to intensive care units. The rapid course of SARS-CoV-2 infection and the severity and progression of lung aberrations require a method of radiological evaluation to implement and manage the appropriate treatment for infected patients. Computed tomography (CT) imaging is considered to be the most effective method for the detection of lung abnormalities, especially in the early stage of the disease. Moreover, serial chest CT imaging with different time intervals is also effective in estimating the evolution of the disease from initial diagnosis to discharge from hospital. Despite having low specificity in distinguishing abnormalities in viral infections, the high sensitivity of CT makes this method ideal for assessing the severity of the disease in patients with confirmed COVID-19. In this review, we present and discuss currently available scales that can be used to assess the severity of lung involvement in COVID-19 patients in everyday work, both for CXR and CT imaging.

Surgeon's viewpoint on lung transplantation in cystic fibrosis patients - preliminary report.

INTRODUCTION: The surgeon's viewpoint on a patient with cystic fibrosis differs from that of a pediatrician or internist. The problems a cystic fibrosis specialist encounters are different from those faced by the surgeon who takes over the patient in a very advanced, often terminal stage of the disease. Hence, the main problem for the surgeon is the decision concerning the surgery (lung transplantation, pneumonectomy, lobectomy). It is, therefore, important to lay down fundamental and appropriate rules concerning the indications and contraindications for lung transplantation, especially in patients with cystic fibrosis. AIM: The aim of this study was to analyze the methods of qualifying and preparing patients for surgery, as well as carrying out the procedure of transplantation and postoperative short and long-term care. MATERIAL AND METHODS: The investigation was carried out on 16 patients with cystic fibrosis. Three were operated on and 10 were on the waiting list for transplantation. Two patients on the waiting list died, one patient was disqualified from transplantation. During qualification for lung transplantation, strict indications, contraindications and other factors (such as blood type, patient's height, coexisting complications) were taken under consideration. RESULTS: All the 3 patients after lung transplantation are alive and under our constant surveillance. Ten patients await transplantation, though four of them are suspended due to hepatitis C infection. Two patients on the waiting list died: one from respiratory insufficiency and the other in the course of bridge to-transplant veno-venous extracorporeal membrane oxygenation due to hepatic failure. One patient has been disqualified because of cachexia. CONCLUSIONS: Since lung transplantation is the final treatment of the end-stage pulmonary insufficiency in cystic fibrosis patients, the number of such procedures in cystic fibrosis is still too low in Poland. The fast development of these procedures is highly needed. It is necessary to develop better cooperation between different disciplines and specialists, especially between pediatricians and surgeons. The correct choice of the suitable moment for lung transplantation is crucial for the success of the procedure.

Using expert-reviewed CSAM to train CNNs and its anthropological analysis.

Machine learning methods for the identification of child sexual abuse materials (CSAM) have been previously studied, however, they have serious limitations. Firstly, the training sets used to train the appropriate machine learning algorithms were not previously annotated by a forensic expert in anthropology. Secondly, previously presented solutions have rarely used models trained using real pornographic content involving children. Thirdly, previous studies have not presented a detailed justification for the classification decisions made, which is important due to the recent guidelines of the European Commission (Artificial Intelligence Act). The aim of the study was to train convolution neural networks (CNNs) using expert-labelled CSAM images and thereby identify the elements of the body and/or the environment that are critical for classifications by the neural network. To train and evaluate machine learning models, we used 60,000 images equally divided into four classes (CSAM images, images displaying sexual activity involving adults, images of people without sexual activity, and images not containing people). We used four neural network architectures: MobileNet, ResNet152, xResNet152 and its modification ResNet-s, designed for the purpose of research. The trained models provided high accuracy of classifying CSAM images: xResNet152 (F1 = 0.93, 92,8%), xResNet-s (F1 = 0.93, 93,1%), ResNet152 (F1 = 0.90, 91,39%), MobileNet (F1 ranged from 0.85 to 0.87, accuracy ranged from 86% to 87%). The results of the conducted research suggest that using expert knowledge (in sexology and anthropology) significantly improved the accuracy of the models. In regard to further anthropological analysis, the results indicate that the breasts, face and torso are crucial areas for the classification of pornographic content with children's participation. Results suggests that the ResNet-s neural network may be a reliable tool for clinical work and to support the work of experts witnesses in the field of anthropology. The study design received a positive opinion of the Ethics Committee of the Faculty of Mathematics, Informatics and Mechanics of the University of Warsaw. The clinical material was used for research purposes with the consent of the relevant prosecutor's offices. Authors provided free version of Windows application to classify CSAM for forensic experts, policemen and prosecutors at the OSF repository (DOI: 10.17605/OSF.IO/RU7JX).

Effect of Intramuscular Tramadol on the Duration of Clinically Relevant Sciatic Nerve Blockade in Patients Undergoing Calcaneal Fracture Fixation: A Randomized Controlled Trial.

BACKGROUND: Calcaneal fracture fixation can generate severe postoperative pain and analgesia can be supported by a sciatic nerve block. However, following resolution of the sensory blockade, rebound pain may ensue. The aim of this study was to assess whether an incidental finding of two patients with an extension of the sciatic nerve block beyond 24 h following 100 mg of intramuscular tramadol administration could be confirmed. METHODS: Thirty-seven patients scheduled for a calcaneal intramedullary fixation (Calcanail®) were randomly divided into two groups. The tramadol group (n = 19) received a sciatic nerve block with 20 mL of 0.25% bupivacaine and a concomitant dose of 100 mg of intramuscular tramadol, while the control group (n = 18) received an identical sciatic nerve block with concomitant injection of normal saline (placebo). All patients had a spinal anesthesia with light sedation for the procedure. The time to first analgesic request defined as appearance of any pain (NRS > 0) was assessed as the primary endpoint with a clinically relevant expected result of at least 50% elongation in sensory blockade. RESULTS: The median time to first analgesic request from time of blockade in the tramadol group was 670 min compared with 578 min in the control group. The result was clinically not relevant and statistically not significant (p = 0.17). No statistical difference could be demonstrated in the time to first opioid request, although a trend for opioid sparing in the tramadol group could be seen. Total morphine consumption in the first 24 h was also statistically insignificant (the tramadol group 0.066 mg kg-1 compared with 0.125 mg kg-1 in the control group). In conclusion, intramuscular tramadol does not extend the duration of analgesia of a sciatic nerve block following a calcaneal fracture fixation beyond 2 h and an opioid sparing effect could not be demonstrated in this trial.

Analysis of Donor to Recipient Pathogen Transmission in Relation to Cold Ischemic Time and Other Selected Aspects of Lung Transplantation-Single Center Experience.

BACKGROUND: Infections are one of the leading causes of death in the early postoperative period after lung transplantation (LuTx). METHODS: We analyzed 59 transplantations and culture results of the donor bronchial aspirates (DBA), graft endobronchial swabs (GES), and recipient cultures (RC) before and after the procedure (RBA). We correlated the results with a cold ischemic time (CIT), recipient intubation time, and length of stay in the hospital and intensive care unit (ICU), among others. RESULTS: CIT of the first and second lungs were 403 and 541 min, respectively. Forty-two and eighty-three percent of cultures were positive in DBA and GES, respectively. Furthermore, positive results were obtained in 79.7% of RC and in 33.9% of RBA. Longer donor hospitalization was correlated with Gram-negative bacteria isolation in DBA. Longer CIT was associated with Gram-positive bacteria other than Staphylococcus aureus in GES and it resulted in longer recipient stay in the ICU. Furthermore, longer CIT resulted in the development of the new pathogens in RBA. CONCLUSION: Results of GES brought more clinically relevant information than DBA. Donor hospitalization was associated with the occurrence of Gram-negative bacteria. Positive cultures of DBA, GES, and RBA were not associated with recipient death.

Hospital Admission Factors Independently Affecting the Risk of Mortality of COVID-19 Patients.

INTRODUCTION: COVID-19 is a disease characterized by high in-hospital mortality, which seems to be dependent on many predisposing factors. OBJECTIVES: The aim of this study was to analyze the clinical symptoms, abnormalities in the results of laboratory tests, and coexisting chronic diseases that independently affected the risk of in-hospital mortality in patients with COVID-19. PATIENTS AND METHODS: We analyzed the records of patients with COVID-19 who were hospitalized from 6 March 2020 to 30 November 2021. RESULTS: Out of the entire group of 2138 patients who were analyzed, 12.82% died during hospitalization. In-hospital mortality was independently associated with older age (OR 1.53, 95% CI 1.20-1.97); lower arterial blood oxygen saturation (OR 0.95, 95% CI 0.92-0.99); the presence of a neoplasm (OR 4.45, 95% CI 2.01-9.62), a stomach ulcer (OR 3.35, 95% CI 0.94-11.31), and dementia (OR 3.40, 95% CI 1.36-8.26); a higher score on the SOFA scale (OR 1.73, 95% CI 1.52-1.99); higher lactate dehydrogenase (LDH) (OR 1.08, 95% CI 1.05-1.12); higher N-terminal pro-brain natriuretic peptide (NT pro BNP) (OR 1.06, 95% CI 1.01-1.11); and lower total bilirubin in blood concentration (OR 0.94, 95% CI 0.90-0.99). CONCLUSIONS: We found that low oxygen saturation, old age, and the coexistence of cancer, gastric ulcers, and dementia syndrome were variables that independently increased mortality during hospitalization due to COVID-19. Moreover, we found that decreased platelet count and bilirubin concentration and increased levels of LDH and NT-proBNP were laboratory test results that independently indicated a higher risk of mortality. We also confirmed the usefulness of the SOFA scale in predicting treatment results. The ability to identify mortality risk factors on admission to hospital will facilitate both adjusting the intensity of treatment and the monitoring of patients infected with SARS-CoV-2.

Description of the neural network based on AB/DL pictures. Possible implications for forensic sexology.

Purpose: Neural networks might be an appropriate solution for the categorization of child sexual abuse materials (CSAM) in forensic cases. The aim of this study was to present a neural network model that may be able to categorize objects and behaviors, which are visible in CSAM, using pictures visually similar to CSAM (AB/DL), involving persons who have paraphilic preferences for watching adult women or men dressed like children or involved in activities typical for children, such as playing. Methods: The dataset consisted of 2251 photos divided into five classes. 1914 photos were randomly used for the training of the neural network, while 337 photos were used for its later validation. The Fast.ai and PyTorch libraries were used for the training of the neural network using the ResNet152 model. We used five classes, two of which were imported from the sexACT dataset, and three of which that were collected for this study. Results: The model was able to classify selected classes with a relatively high accuracy (95%); on the other hand, further improvement of the network is needed, considering the fact that the final validation loss was moderate (0.17). Conclusions: The model presented might be effective in the classification of several objects and behaviors presented in a number of pornography categories ("paraphilic infantilism", "sexual activity", "nude women", "dressed women", "sexual activity - spanking"). As the results are promising, further research on real CSAM is justified.

Methodology of estimation of temperature mode in the 2xBgu type railway braking system.

The article presents finite element models of the 2xBgu type tread brake for the simulation of extended repeated frictional heating carried out on a full-scale inertia dynamometer. The numerical calculations were conducted for the brake blocks made of two organic composite materials newly developed specifically for this study. The transient temperature changes obtained from the 2D axisymmetric and 3D finite element analyses and experimental data agreed well during continuous process of about 1200 s. Simulation of such a long period of braking sequence required introducing simplifications in the boundary conditions in the contact area, convection cooling, arrangement of the model (2D axisymmetric, 3D). The focus was laid on representation of variation of the coefficient of friction and the temperature dependence of the properties of the friction materials during braking. The carried out research indicates limitations in the finite element analysis and directions of necessary improvements in modelling as well as measurements with the use of embedded thermocouples.

Does Hospitalization Change the Perception of COVID-19 Vaccines among Unvaccinated Patients?

The COVID-19 vaccination has been the subject of unprecedented misinformation, false news, and public concerns. This study presents a unique analysis comprising persons who were not vaccinated and became ill. It investigates reasons for not vaccinating and evaluates how the personal experience of COVID-19 affected further attitudes and decisions related to health. The study included 730 consecutive unvaccinated patients hospitalized in 12 centers in Poland during the autumn 2021 pandemic wave. The most frequent reason behind the refusal to receive the vaccine was concern over the adverse effects, disbelief that the vaccine was sufficiently tested, and one's conviction that COVID-19 will not affect a patient. Online information, friends, spouse, children/grandchildren, and other family members were most often the source of discouragement from vaccination. Most individuals regretted their decision not to receive a vaccine (66.0%), declared to promote COVID-19 vaccination after discharge (64.0%), and to receive a COVID-19 vaccine in the time recommended for convalescents (69.5%). Individuals expressing no regrets of vaccine refusal more frequently revealed conspiracy beliefs. The study shows that personal experience with severe COVID-19 can influence the perception of vaccination, but approximately one-third of unvaccinated hospitalized patients still appear to express vaccine hesitancy.

The Clinical Course and Outcomes of Patients Hospitalized Due to COVID-19 during Three Pandemic Waves in Poland: A Single Center Observational Study.

Background: The first case of coronavirus disease 2019 (COVID-19) in Poland was reported on 4 March 2020. We aim to compare the clinical course and outcomes of patients hospitalized in the Hospital for Infectious Diseases in Warsaw due to COVID-19 during three pandemic waves. Materials and methods: The medical data were collected for all patients diagnosed with COVID-19 hospitalized in our hospital from 6 March 2020 till 30 November 2021. COVID-19 diagnosis was confirmed by nasopharyngeal swabs using real-time polymerase chain reaction assay (RT-PCR) or SARS-CoV-2 antigen test. COVID-19 waves were defined based on the number and dynamics of cases. Results: Altogether, 2138 patient medical records were analyzed. The majority of the cohort was male (1235/2138, 57.8%), and the median age was 65 years [IQR: 50−74 years]. Patients hospitalized during the third wave had lower oxygen saturation on admission (p < 0.001) and were more likely to receive oxygen supplementation (p < 0.001). Serious complications, including pneumothorax (p < 0.001) and thromboembolic complications (p < 0.001), intensive care unit admission (p = 0.034), and death (p = 0.003), occurred more often in patients of the third wave. Conclusions: During the third wave, patients in our cohort experienced a more severe course of the disease and poorer outcomes.

Comparative Analysis of Temperature Fields in Railway Solid and Ventilated Brake Discs.

A new approach to numerical simulation using the finite element method (FEM) for the rotational motion of discs for railway vehicle disc brake systems was proposed. For this purpose, spatial models of transient heating due to the friction of such systems with solid and ventilated discs were developed. The performed calculations and the results obtained allowed justification of the possibility of simplifying the shape of the ventilated brake disc through elimination of ventilation channels. This contributes to a significant reduction in computational time, without compromising the accuracy of the results. The spatial and temporal temperature distributions in the ventilated and the solid disc of the same mass were analyzed. The share of energy dissipated due to convection and thermal radiation to the environment in relation to the total work done during a single braking was investigated. The maximum temperature values found as a result of computer simulations were consistent with the corresponding experimental results.

Radiological Manifestation of Neurological Complications in the Course of SARS-CoV-2 Infection.

Many reports suggest the SARS-CoV-2 infection may result in neurological complications. A wide spectrum of clinical syndromes have been reported, including both central and peripheral nervous system. Such symptoms may be a consequence of a direct viral injury, secondary to systemic inflammatory response, autoimmune processes, ischemic lesions or combination of these. Anosmia and dysgeusia are highly prevalent in the early stage of infection. Cerebrovascular events in patients with COVID-19 have also been documented with increasing frequency. Some cases of parainfectious autoimmune neurologic manifestations concurrent with active SARS-CoV-2 infection have been described, including hemorrhagic necrotizing encephalopathy, Guillain-Barré and Miller-Fisher syndromes. There are also a few reports documenting encephalitis and acute demyelinating encephalomyelitis (ADEM) in the course of COVID-19. There is also a growing number of cases of patients after recovery from COVID-19 with psychosomatic disorders, manifesting with memory disfunction, cognitive functions disorders, depression or other affective disorders, which may lead to a decrease of intellectual functions. Many of these neurological manifestations of the infection are possible to distinguish using radiological imaging techniques. It plays a very important role in evaluating the course of COVID-19 as well as diagnosing respiratory complications and choosing a proper management of infected patients. Similarly, radiological techniques play crucial role in identifying the cause of neurological symptoms connected to SARS-CoV-2 infection, being one of the most important elements of diagnostics. Especially in case of the presence of nervous system implication, using radiological imaging techniques to monitor the emerging onset of various symptoms is crucial to assess the severity and scope of involvement. Quick diagnostic process and identifying complications as fast as possible in order to implement specific treatment can be crucial to avoid long-term secondary conditions and accelerate the recovery period. In this review, we present the most important neurological complications that may occur in the course of SARS-CoV-2 infection and summarize their radiological manifestations.

A Comparison of 3D and 2D FE Frictional Heating Models for Long and Variable Applications of Railway Tread Brake.

The article proposes two 3D and 2D numerical FE models of frictional heating for the estimation of temperature distributions in railway tread brake in 1xBg configuration during repeated long-term braking. The results of computations were compared with the time courses of temperature measured using thermocouples throughout the duration of the tests on a full-scale dynamometer for two different brake shoe materials in combination with a steel wheel. The resulting temperature distributions calculated using the proposed models agreed well with the experimental measurements, and the maximum difference in temperature values does not exceed 20%. It has been proven that 2D FE model can be as efficient as 3D model to estimate the temperature distribution during long-term and variable braking in the considered friction node. The differences in the calculation of the temperature values using these models did not exceed 3%, and the calculation time for the 2D model, compared to the 3D model, was shorter approximately 85 times for the braking cycle lasting 5032 s, and approximately 45 times for the braking cycle lasting 3297 s.

Treatment of pathological fractures due to brown tumours in a patient with hyperparathyroidism and lack of parafibromin expression - A case report.

Brown tumours, known also as osteitis fibrosa cystica, are benign osteolytic lesions found in 5-15% of patients with hyperparathyroidism, and commonly located in mandibles, the shafts of long bones, the pelvis or ribs. As they compromise bone strength, pathological fractures can be a typical effect of their presence; but given the complex nature of the disease process in this case, such fractures require an interdisciplinary approach directed at orthopaedic treatment, plus management of the underlying hyperparathyroidism. In this paper, we present the case of a 36-year-old female patient with bilateral anophthalmia, hyperparathyroidism and nephrolithiasis, in whom a fall led to her sustaining a pathological fracture of the proximal third of the femoral shaft in the place of an osteolytic lesion, as well as second pathological fracture of the left patella also changed by multiple examples of such lesions. Parathyroidectomy on account of adenoma had been performed 2 weeks prior to the trauma. The femoral shaft fracture was treated surgically, the patella fracture conservatively, and a sample brown tumour was found in tissue. As the parathyroid showed no parafibromin expression, a diagnosis of HPT-JT (hyperparathyroidism and jaw tumour) was arrived at, with this condition given as caused by CDC73 mutation. This disease is able to account for brown tumours, hyperparathyroidism, benign or malignant tumours of kidneys, intestinal tract, and lungs. The approach combining treatment of the fractures with intervention over the parathyroid adenoma proved a successful one, with complete bone union ensuing, and no relapse into hyperparathyroidism 2 years on from the surgery. This case indicates the importance of an interdisciplinary approach to the treatment of brown tumours, as well as the necessity for a diagnosis to be extended when incidental brown tumours are found.