Estimation of the Path-Loss Exponent by Bayesian Filtering Method.

Regarding wireless sensor network parameter estimation of the propagation model is a most important issue. Variations of the received signal strength indicator (RSSI) parameter are a fundamental problem of a system based on signal strength. In the present paper, we propose an algorithm based on Bayesian filtering techniques for estimating the path-loss exponent of the log-normal shadowing propagation model for outdoor RSSI measurements. Furthermore, in a series of experiments, we will demonstrate the usefulness of the particle filter for estimating the RSSI data. The stability of this algorithm and the differences in determined path-loss exponent for both method were also analysed. The proposed method of dynamic estimation results in significant improvements of the accuracy of RSSI values when compared with the experimental measurements. It should be emphasised that the path-loss exponent mainly depends on the RSSI data. Our results also indicate that increasing the number of inserted particles does not significantly raise the quality of the estimated parameters.

The impact of the COVID-19 pandemic on higher education: Assessment of student performance in computer science.

The COVID-19 pandemic had radically changed higher education. The sudden transition to online teaching and learning exposed, however, some benefits by enhancing educational flexibility and digitization. The long-term effects of these changes are currently unknown, but a key question concerns their effect on student learning outcomes. This study aims to analyze the impact of the emergence of new models and teaching approaches on the academic performance of Computer Science students in the years 2019-2023. The COVID-19 pandemic created a natural experiment for comparisons in performance during in-person versus synchronous online and hybrid learning mode. We tracked changes in student achievements across the first two years of their engineering studies, using both basic (descriptive statistics, t-Student tests, Mann-Whitney test) and advanced statistical methods (Analysis of variance). The inquiry was conducted on 787 students of the Lublin University of Technology (Poland). Our findings indicated that first semester student scores were significantly higher when taught through online (13.77±2.77) and hybrid (13.7±2.86) approaches than through traditional in-person means as practiced before the pandemic (11.37±3.9, p-value < 0.05). Conversely, third semester student scores were significantly lower when taught through online (12.01±3.14) and hybrid (12.04±3.19) approaches than through traditional in-person means, after the pandemic (13.23±3.01, p-value < 0.05). However, the difference did not exceed 10% of a total score of 20 points. With regard to the statistical data, most of the questions were assessed as being difficult or appropriate, with adequate discrimination index, regardless of the learning mode. Based on the results, we conclude that we did not find clear evidence that pandemic disruption and online learning caused knowledge deficiencies. This critical situation increased students' academic motivation. Moreover, we conclude that we have developed an effective digital platform for teaching and learning, as well as for a secure and fair student learning outcomes assessment.

The Relationship between Cancer Stage, Selected Immunological Parameters, Epstein-Barr Virus Infection, and Total Serum Content of Iron, Zinc, and Copper in Patients with Laryngeal Cancer.

(1) Background: the purpose of the study was to assess the relationship between cancer stage, selected immunological parameters, Epstein-Barr virus (EBV) infection, and total serum content of iron, zinc, and copper in patients with laryngeal cancer (LC). (2) Methods: serum Fe, Zn, and Cu were measured in 40 LC patients and 20 controls. Immunophenotyping of peripheral blood lymphocytes was performed by flow cytometry using fluorescent antibodies against CD3, CD4, CD8, CD19, CD25, CD69, and PD-1. Tumor and lymph node lymphocytes were analyzed by flow cytometry. EBV DNA was quantified by real-time PCR, targeting the EBNA-1 gene. Associations between serum elements, immune markers, and cancer grade/stage were evaluated using ANOVA and appropriate nonparametric tests. (3) Results: levels of Fe, Cu, and Zn were lower, while Cu/Zn was statistically higher, in patients with LC than in the control group. Correlation analysis showed a statistically significant association between the levels of these elements and parameters of the TNM (Tumor, Node, Metastasis) staging system, immunophenotype, and the amount of EBV genetic material in patients with LC who survived for more than 5 years. (4) Conclusion: the results suggest that the total serum levels of the determined micronutrients may significantly affect the immunopathogenesis and progression of LC.

The Clinical, Pathological, and Prognostic Value of High PD-1 Expression and the Presence of Epstein-Barr Virus Reactivation in Patients with Laryngeal Cancer.

Due to the development of molecular diagnostic techniques, the latest research in the diagnosis of cancer diseases, including laryngeal cancer, has been focused on the occurrence of specific types of molecular patterns, including markers expressed on cells of the immune system (e.g., PD-1, PD-L1, and CTLA-4), which may be directly or indirectly involved in the development of neoplastic diseases. Laryngeal cancer is one of the diseases that is diagnosed more often in men than in women, and many factors are involved in its development, including environmental and lifestyle factors, viral infections (e.g., HPV, HHV-1, and EBV), and disorders of the immune system. In this study, we determined the level of PD-1 receptor expression on T and B lymphocytes and their relationships based on the classification of the grade and TNM scale, in turn based on blood, tumor, and lymph node samples from patients diagnosed with laryngeal cancer. In addition, we determined the presence of EBV genetic material in the tested biological materials as well as the degree of cancer advancement and its correlation with the level of PD-1 receptor expression. The results suggested that the level of PD-1 expression on T and B lymphocytes was significantly higher in the tumor samples as compared to the lymph node samples, and their comparison with the immunophenotype results from the blood samples provided statistically significant data on changes in the incidence of individual subpopulations of T and B lymphocytes and the level of PD-1 receptor expression. The analysis of the individual parameters of the TNM scale also showed significant changes between the PD-1 expression and the tested biological material in individual subgroups of the scale. We also found that the expression of PD-1 on the CD4+ T cells from the lymph node samples caused an almost 1.5-fold increase in the risk of death. In the analyses of the presence of EBV, the highest concentration was recorded in the tumor samples, then for the lymph node samples, and followed by the blood samples. Furthermore, we showed that the presence of EBV genetic material was positively correlated with the level of PD-1 expression in the tested biological materials.

Th17 and Treg cells in adolescents with Graves' disease. Impact of treatment with methimazole on these cell subsets.

The role of T helper 17 (Th17) and T regulatory cells (Treg) in the pathogenesis of Graves' disease (GD) remains uncertain. The influence of methimazole (MMI) on the human immune system is still poorly understood. The aim of the present research was to assess changes in the frequencies of peripheral blood Th17 and Treg cells during GD treatment in the group of teenagers. The frequencies of Th17 and Treg were measured by flow cytometry in 60 adolescents at the time of GD diagnosis and after achieving MMI-induced euthyreosis. The control group consisted of 20 healthy volunteers. Lower percentages and absolute counts of Treg cells were found in the study group before the treatment in comparison with healthy controls (p = 0.032 and p = 0.006, respectively). Treatment with MMI caused an increase in the percentages and absolute counts of Treg lymphocytes (p = 0.037 and p = 0.007). After the treatment, no clinically significant differences in Treg cells between GD patients and controls were found. Higher absolute counts of Th17 lymphocytes were found in hyperthyroid adolescents before the treatment initiation and after achieving euthyreosis than in healthy individuals (p = 0.0001 and p = 0.047). Treatment with MMI caused a significant decrease in the percentages and absolute counts of Th17 lymphocytes (p = 0.047 and p = 0.043). The present study demonstrates that both Th17 and Treg cells might play a role in the pathogenesis of GD. Increased percentage of Treg after MMI therapy seems a predictor of response to anti-hypertensive treatment as it is associated with the normalization of thyroid hormone levels.

Impact of methimazole treatment on magnesium concentration and lymphocytes activation in adolescents with Graves' disease.

The aim of this research was to assess plasma magnesium (Mg) concentration, the frequencies of activated T CD4+ and T CD8+ lymphocytes and B lymphocytes in adolescents with hyperthyroidism due to Graves' disease (GD), and to assess changes in the above-mentioned parameters during methimazole (MMI) treatment. The frequencies of activated T and B cells were measured by flow cytometry method and plasma Mg concentration was determined by spectrophotometry method in 60 adolescents at the time of GD diagnosis and after receiving the normalisation of the thyroid hormones levels. The control group consisted of 20 healthy volunteers. We observed lower plasma Mg concentration, and higher frequencies of activated T and B lymphocytes in the study group before the treatment in comparison with healthy controls, and with study group in MMI-induced euthyreosis (p < 0.01).Statistically significant negative correlations between the percentages of activated T CD3+, T CD4+, T CD8+ and B CD19+ lymphocytes, and plasma Mg concentration before the treatment were found (r < -0.335, p < 0.002). After the treatment no vital differences in plasma Mg concentration, and in percentages of activated cells between GD patients and controls were found, except CD8+CD25+ cells (p = 0.03). The present study demonstrates that both activated T and B cells might play an important role in the pathogenesis of GD, and activation is related to Mg plasma level. The use of MMI in treatment of hyperthyroidism due to GD leads to decrease the frequencies of activated lymphocytes and normalisation of Mg levels.

The content of cadmium, cobalt and nickel in laryngeal carcinoma.

INTRODUCTION: The aim of the study was to determine the content of cadmium (Cd), cobalt (Co) and nickel (Ni) in the samples from laryngeal carcinoma in comparison with the level of these elements in the samples of healthy mucous membrane from the same larynx. MATERIAL AND METHODS: The study was conducted on 43 patients with laryngeal carcinoma. The levels of Cd, Co, and Ni in carcinoma and healthy control tissues was determined by inductively coupled plasma optical emission spectrometry (ICP - OES) using sequential spectrometer. RESULTS: No significant differences were found between the levels of the Cd, Co, and Ni in laryngeal carcinoma vs tissues without carcinoma. However, it was noted that the concentration of Cd in tumors of patients with metastases to cervical lymph nodes was significantly higher than in tumors without metastases. The content of Co was significantly higher in more advanced laryngeal tumors: in stage-T4 than in stage T3. It is of interest that the levels of Cd, Co and Ni were significantly higher in tumors in patients from rural than urban areas. CONCLUSIONS: The imbalance in the level of nickel, cadmium and cobalt in laryngeal cancer may be due to a changed cellular metabolism in the cancer process. However, the results of our study reveal the significant differences in the concentration of these metals between patients from urban and rural areas which suggests that this fact may be related to environmental or occupational factors and therefore it requires further study.