ABSTRACT
Long-term exposures to environmental factors including airborne as well as noise pollutants, are associated with cardiovascular risk. However, the influence of environmental pollution on the young population is controversial. Accordingly, we aimed to investigate the relationships between long-term exposures to different environmental factors and major cardiovascular and inflammatory parameters and biomarkers in young, healthy subjects. Representative sample of permanent residents of two cities differing in air and noise pollution levels, aged 15-21 years, were recruited. Krakow and Lublin, both located in southern Poland, were chosen in relation to their similarities in demographic and geopolitical characteristics, but differences in air pollution (higher in Krakow) and noise parameters (higher in Lublin). A total of 576 subjects were studied: 292 in Krakow and 284 in Lublin. All subjects underwent health questionnaire, blood pressure measurements and biomarker determinations. Inflammatory biomarkers, such as CRP, hs-CRP, fibrinogen as well as homocysteine were all significantly higher in subjects living in Krakow as opposed to subjects living in Lublin (for hsCRP: 0.52 (0.32-0.98) mg/l vs. 0.35 (0.22-0.67) mg/l; p < 0.001). Increased inflammatory biomarker levels were observed in Krakow in both male and female young adults. Interestingly, significant differences were observed in blood pressure between male and female subjects. Males from Krakow had significantly higher mean systolic blood pressure (127.7 ± 10.4 mm/Hg vs. 122.4 ± 13.0 mm/Hg; p = 0.001), pulse pressure (58.7 ± 8.9 mm/Hg vs. 51.4 ± 12.3 mm/Hg; p < 0.001) and lower heart rate (p < 0.001) as compared to males living in Lublin. This was not observed in young adult females. Long-term exposure to environmental factors related to the place of residence can significantly influence inflammatory and cardiovascular parameters, even in young individuals. Interestingly, among otherwise healthy young adults, blood pressure differences exhibited significant variations based on biological sex.
Subject(s)
Biomarkers , Blood Pressure , Environmental Exposure , Inflammation , Humans , Male , Female , Young Adult , Environmental Exposure/adverse effects , Adolescent , Inflammation/blood , Biomarkers/blood , Poland/epidemiology , Sex Factors , Adult , Healthy Volunteers , Hypertension/etiology , Hypertension/epidemiology , Air Pollution/adverse effects , Air Pollution/analysisABSTRACT
This descriptive study determined whether winter swimming (WS) and outdoor amateur running (RUN) affect blood morphological and biochemical indicators in men during midseason winter swimming from November to April. There were three groups of participants, with 10 male amateurs each: RUN + WS, WS, and control. The research was performed in the middle of the winter swimming season of 2020/2021. This time period was chosen in consideration of the respondents' adaptation to winter conditions. The study involved only 10 male amateurs in each study group owing to COVID-19 pandemic restrictions, which confined people to their homes. In the RUN + WS group compared with the WS group, significant decreases in the mean corpuscular hemoglobin concentration (within standard limits) (p = 0.04) and platelet distribution width (p = 0.006) were observed, with a significant increase in the red blood cell distribution width (p = 0.008) (within standard limits). The renal function, as expressed by the estimated glomerular filtration rate, was higher in the RUN + WS group (p = 0.02) (within standard limits) compared with the WS group, and the uric acid concentration was reduced (p = 0.01). In the RUN + WS group compared with the control group, significant decreases in the leukocyte count (p = 0.02) (within standard limits), monocyte count (p = 0.04) (within standard limits), and platelet distribution width (p = 0.005) were reported. The remaining indicators presented a p-value > 0.05. The two investigated forms of physical activity had no negative effect on blood morphological or biochemical indicators in male amateurs during the winter swimming midseason.
ABSTRACT
The aim of the study was to investigate whether 20 whole-body cryotherapy treatments have an effect on oxidative-antioxidant imbalances in women with multiple sclerosis. Fifty women aged 30-55 were examined: study group-15 women with multiple sclerosis, subjected to whole-body cryotherapy; first control group-20 women with multiple sclerosis who did not receive cryotherapy intervention; second control group-15 healthy women who participated in cryotherapy treatments. Blood from the examined women was collected twice (before and after the series of 20 cryotherapy sessions). An insignificant increase in the total antioxidant capacity (study group: p = 0.706; second control group: p = 0.602) was observed after the whole-body cryotherapy intervention. After the series of cryotherapy sessions, the total oxidative status/total oxidative capacity value was insignificantly decreased among the multiple sclerosis patients (decrease by 14.03%, p = 0.495). In women with multiple sclerosis, no significant cryotherapy impact was demonstrated on changes in the oxidant-antioxidant imbalance or concentrations of nitric oxide, uric acid, or matrix metalloproteinase-9.
ABSTRACT
There is a global problem with the effective purification of wastewater containing organic compounds, including dyes, pharmaceuticals and surfactants. Therefore, technologies for the removal of pollutants are still being explored. One of the promising methods could be the application of mineral sorbent composite based on lignite and bentonite. However, it is crucial to comprehensively recognize the mechanisms responsible for immobilizing organic compounds using mineral composite sorbents. The purpose of this work was to prepare and investigate the sorption mechanism of lignite-bentonite composite (BL) sorbents for the removal of dyes: Rhodamine B (RB), Remazol Brilliant Blue R (RBBR), pharmaceuticals: ibuprofen (IB), sulfamethoxazole (STX) and surfactant sodium dodecylbenzenesulfonate (SDBS). The quantitative sorption results have been performed using the high-performance liquid chromatography (HPLC) method. The application of infrared (IR) spectroscopy method was crucial to describe the sorption mechanism. After completing the sorption test, the spectra for the sorbents revealed bands associated with adsorbed RB, RBBR, IB, STX, and SDBS on the BL sorbent. Because lignite is predominated in BL composite, the sorption capacity and mechanism strictly correspond to its sorption properties rather than to bentonite ones. The spectra results indicate that the physical sorption process related to electrostatic forces, hydrogen bonding, and dispersion interactions are predominantly responsible for the immobilization of organic compounds tested on mineral sorbents. The X-ray diffraction (XRD) results indicate the ion exchange process involved in the case of RB adsorption on the bentonite sample. Nevertheless, the sorption mechanism was complex because of the extensive sorption properties of mineral composite and the different chemical properties of the tested organic compounds. The results of our spectroscopic studies help interpret the sorption mechanisms of organic compounds on mineral materials.
ABSTRACT
Balneotherapy is an effective treatment method in various diseases and commonly used treatment modality among patients with musculoskeletal disorders. Sulfur baths are known for healing properties however effect on rheological properties is unstudied. Thus the aim of our study was to determine the effect of sulfur balneotherapy on hemorheological blood indices. A total of 48 patients with osteoarthritis were enrolled to the study. Blood samples were collected twice, before and after 3-week time period. We evaluated complete blood count, fibrinogen, hs-CRP and blood rheology parameters such as elongation index (EI), half-time of total aggregation (T1/2) and aggregation index (AI) analyzed with the Lorrca Maxis. Mean age of studied cohort was 67 ± 5 years. After sulfur baths WBC count was significantly decreased is studied group (p = 0.021) as well as neutrophile count (p = 0.036). Red blood cell EIs were statistically higher after sulfur baths in shear stress ranging from 8.24 to 60.30 Pa. T1/2 was significantly higher (p = 0.031) and AI lower (p = 0.003) compared to baseline. No significant changes in fibrinogen and hs-CRP were observed. It is the first study that evaluate effect of sulfur balneotherapy on rheologic properties of blood. Sulfur water baths may improve erythrocyte deformability and aggregation parameters.
Subject(s)
Hemorheology , Osteoarthritis , Humans , Middle Aged , Aged , Baths , C-Reactive Protein/pharmacology , Erythrocyte Deformability , Blood Viscosity , Osteoarthritis/therapy , Fibrinogen/analysis , Sulfur/pharmacology , Erythrocyte AggregationABSTRACT
PURPOSE: A great number of patients that suffer from lateral epicondylitis, commonly called tennis elbow (TE), are not successfully treated, meaning, not getting adequate therapeutic effects and the main origin of the pain not being handled appropriately. The hypothesis of the present study is that the inefficiency of the treatment of the chronic TE may often be due to underdiagnosis of posterior interosseous nerve (PIN) entrapment or and plica syndrome, as the authors believe that those pathologies can often occur simultaneously. METHODS: A prospective cross sectional study was conducted. A total of 31 patients met the required criteria. RESULTS: Thirteen (40.7%) of the patients had more than one source of the lateral elbow pain. Five patients (15.6%) had all three examined pathologies. Six patients (18.8%) had TE and PIN syndrome. Two patients (6.3%) had TE and plica syndrome. CONCLUSION: The present study demonstrated concomitant potential sources of lateral elbow pain in patients diagnosed with chronic TE. Our analysis shows how important it is to systematically diagnose patients that present with lateral elbow pain. The clinical characteristics of the three most common causes of chronic lateral elbow pain, meaning, TE, PIN compression, and plicae syndrome were also analyzed. Having adequate knowledge about the clinical aspects of these pathologies can help with a more effective differentiation of the etiology of chronic lateral elbow pain, and with that, a more efficient and cost-effective treatment plan.
Subject(s)
Chronic Pain , Synovitis , Tennis Elbow , Humans , Tennis Elbow/complications , Tennis Elbow/diagnosis , Cross-Sectional Studies , Prospective Studies , Arthralgia/diagnosisABSTRACT
The nanocomposite coatings composed of carbon nanotubes and various forms of copper were prepared in the two-step process. Firstly, carbon nanotubes were coated on stainless steel substrate using electrophoretic deposition at constant current. Then, the process of electrochemical deposition using copper(II) sulphate solutions was performed under high overpotential conditions. The modification of the copper(II) cations concentration in the solution and the deposition time provided the formation of various forms of crystals. The samples and their cross-sections were observed and examined using scanning electron microscope equipped with electron dispersive spectroscopy system. The analysis of chemical composition revealed that in addition to the pure copper crystals, the crystals characterized by the presence of copper and oxygen were formed. Therefore, Raman spectroscopy was applied to determine the unknown stoichiometry of this copper oxide. The point and in-depth analysis identified copper(I) oxide in the form of different size crystals depending on the concentration of the copper(II) sulphate solution. To confirm these findings, grazing incidence X-ray diffraction measurements were also performed. the combination of the applied methods has provided the detailed description of the preparation of the nanocomposite coatings with the proposed mechanism of copper(I) oxide formation.
ABSTRACT
The aim of this study was to analyze the selected hematological and rheological indices in female rowers during the competitive season. The study included 10 female rowers (aged 21.2 ± 2.6) and the control group consisted of 10 woman of corresponding age (non-athletes). The examination of athletes took place two times: at the beginning of the season during high endurance low intensity training period in January (baseline) and at the end of the competitive season in October (after). Blood samples taken from all woman were analyzed for hematological and rheological parameters. The training period of rowers during the 10 months resulted in decrease in red blood cell count and RBC deformability, in contrast to an improvement in some rheological functions such a decrease in fibrinogen concentration, plasma viscosity and aggregation index. The training program practice in rowing modulated some hematological and rheological indices. Some of them positively influenced the cardiovascular system and reduced potential risks connected with hard training and dehydration, but others may have followed from overtraining or not enough relaxation time between training units.
Subject(s)
Endurance Training , Water Sports , Humans , Female , Rheology/methods , Athletes , Fibrinogen , Blood ViscosityABSTRACT
The study assessed the effect of 3-week intermittent hypoxic training on blood biochemical indicators (blood morphology, fibrinogen), blood rheological properties (erythrocyte deformability, aggregation), erythrocyte enzymatic activity (acetylcholinesterase), and maximal oxygen uptake in competitive rowers. Fourteen male rowers were divided into two equal groups: experimental, training on ergometers under normobaric hypoxia (FiO2 = 16.0%), and control, training on ergometers under normoxia (FiO2 = 21%). Fasting blood was taken before and after training. A significant between-group difference in neutrophil levels before training was noted and a significant decrease in white blood cells in the hypoxia group. Both groups exhibited an increase in elongation index. In the normoxia group, a significant increase in erythrocyte aggregation amplitude was revealed. No significant changes occurred in the other biochemical indicators or those evaluating erythrocyte metabolic activity. Normobaric hypoxia increased erythrocyte deformability, improving blood rheological properties. Maximal oxygen uptake significantly increased only in the experimental group.
ABSTRACT
The importance of physical activity in preventing chronic cardiovascular and metabolic diseases and the role of exercise as an adjunct therapy are widely recognized. Triathlon is a typically endurance discipline. Prolonged and intensive exercise is known to cause changes in blood rheological properties and biochemical markers; sometimes athletes participating in strenuous competitions need medical attention. To understand the phenomena occurring in the body in such situations, we decided to study participants' biomarkers after the XTERRA Poland 2017 triathlon competition. The study involved 10 triathletes. The XTERRA Poland 2017 event comprised 1500-m swimming, 36-km cycling, and 10-km mountain running. Blood samples were collected 2 days before, immediately after, and 16 h after the competition. Immediately after the race, white blood cells count, platelets, and uric acid levels were significantly (P < 0.001) increased; haematocrit, Na+, Cl-, and IgA were decreased. On the following day, Na+, Cl-, and C-reactive protein levels were significantly (P < 0.001) increased; white blood cells count, red blood cells count, haemoglobin, haematocrit, mean corpuscular volume, platelets, IgG, and IgA were decreased. Assessing rheological parameters such as erythrocyte deformability and aggregation is useful for monitoring adverse effects of intensive and exhaustive exercise. The study illustrates the change in blood rheological properties and biochemical markers after intensive physical effort. Despite these differences, the indicators were within the reference range for the general population, which may demonstrate normal body function in the studied triathletes.
Subject(s)
Running , Biomarkers , Humans , Immunoglobulin A , Physical Endurance , Poland , SwimmingABSTRACT
Nanocomposites developed based on siloxanes modified with carbon nanoforms are materials with great application potential in the electronics industry, medicine and environmental protection. This follows from the fact that such nanocomposites can be endowed with biocompatibility characteristics, electric conductivity and a high mechanical durability. Moreover, their surface, depending on the type and the amount of carbon nanoparticles, may exhibit antifouling properties, as well as those that limit bacterial adhesion. The paper reports on the properties of polysiloxane (PS) and carbon nanotubes (CNT) nanocomposite coatings on metal surfaces produced by the electrophoretic deposition (EPD). A comparison with coatings made of pure PS or pure CNT on the same substrates using the same deposition method (EPD) is provided. The coatings were examined for morphology and elemental composition (SEM, EDS), structural characteristics (confocal Raman spectroscopy), electrical conductivity and were tested for corrosion (electrochemical impedance spectroscopy-EIS, potentiodynamic polarization-PDP). The results obtained in this study clearly evidenced that such hybrid coatings conduct electricity and protect the metal from corrosion. However, their corrosion resistance differs slightly from that of a pure polymeric coating.
Subject(s)
Nanotubes, Carbon , Coated Materials, Biocompatible/chemistry , Corrosion , Durapatite/chemistry , Electric Conductivity , Nanotubes, Carbon/chemistry , SiloxanesABSTRACT
OBJECTIVES: The aim of this study was thus to assess the stress level among dental students, characterizing the factors that induce it and describing which students are most susceptible. METHODS: Two international, independent and validated to polish language and environment stress questionnaires were used: the Perceived Stress Scale (PSS-10) and the Perceived Medical School Stress Instrument (PMSS). The present study received approval from the Jagiellonian University Bioethical Committee (no. 1072.6120.290.2020). RESULTS: A total of 272 students from all five years of the dental undergraduate degree at Jagiellonian University Medical College were enrolled to the study, including 197 female and 75 male respondents. The overall response rate was 85%. The PSS-10 score for all dental students was 22.14±6.65. A total of 182 (66.91%) respondents had high levels of stress. Female students had significantly higher stress levels than male students, accordingly 22,9±6,51 and 20,12±6,69. Moreover, first and fifth year students had the highest stress level. In the case of PMSS the total score for all dental students was 36.84±8.65. CONCLUSIONS: Perceived stress among Polish dental students is generally high. These findings suggest that support services should be made widely available to all dental students. Such services should be targeted to the specific needs of male and female students as well as to those in specific years of study.
Subject(s)
Stress, Psychological , Students, Dental , Humans , Male , Female , Stress, Psychological/etiology , Surveys and Questionnaires , UniversitiesABSTRACT
O b j e c t i v e s: Accidental exposure to non-fire related carbon monoxide (CO) in young people is largely unquantified. Our aim was to estimate the possibility of exposure to CO and the awareness of intoxication in the population of students living in Kraków, one of the largest academic cities in Poland. M e t h o d s: Anonymous questionnaires about CO poisoning were distributed among medical and non-medical students living in Kraków. R e s u l t s: 1081 questionnaires were collected - 16% of study participants knew a person who had been poisoned with carbon monoxide, 51.2% of students using a bathroom water heater believed that they had no risk of CO poisoning. Medical students gained significantly higher scores in the CO-poisoning knowledge test than non-medical ones. C o n c l u s i o n s: There is still unsatisfactory awareness of CO poisoning among non-medical students in Kraków.
Subject(s)
Carbon Monoxide Poisoning , Students, Medical , Adolescent , Carbon Monoxide Poisoning/epidemiology , Humans , Poland/epidemiology , Surveys and QuestionnairesABSTRACT
INTRODUCTION: Despite the widespread availability of vaccines, the incidence of vaccine-preventable childhood diseases (VPCD) started to grow in recent years. The aim of the study was to compare the annual incidence of selected VPCDs in the EU (European Union) and EFTA (European Free Trade Association) countries in the period of the last 5 years (2014-2019 or other intervals, depending on data availability), and the country-specific vaccine schedules. METHODS: VPCD incidence rates in Europe were based on "The Surveillance Atlas of Infectious Diseases" by the ECDC (European Centre for Disease Prevention and Control); vaccination schedules were based on ECDC reports. RESULTS: The obligation to vaccinate was not universal, and it generally only applied to two preparations: the MMR (measles, mumps, rubella) vaccine and the one against polio. During the study, the situation associated with mumps did not change or improve in individual countries; the median incidence amounted to 30 cases. The median incidence associated with rubella amounted to 1 case, but in a few countries, it grew very rapidly, i.e., in Germany, Italy, and Romania; in Poland, the incidence was clearly decreasing, from 5923 to 1532 cases. The most dynamic situation concerned measles. The total median was 2.4 cases per 100,000 population; the only one country with falling incidence was Germany. The diseases associated with Streptococcus pneumoniae and Neisseria meningitidis remained at a stable level in all analyzed countries. CONCLUSION: Vaccine schedules differ among the countries, so does the epidemiological situation of selected diseases. Morbidity on measles was the most disturbing phenomenon: the incidence rate increased in almost 40% of all countries, regardless of the obligation to vaccinate. The increasing incidence of VPCD may be due to anti-vaccine movements, the activity of which is often caused by mistrust and spreading misinformation. In order to better prevent the increase in morbidity, standardization of vaccine schedules and documentation should be considered in the EU countries.
ABSTRACT
The aim of this study was to examine and assess the impact of a series of 20 whole-body cryotherapy (WBC) treatments on the biochemical and rheological indices of blood in people with multiple sclerosis. In this prospective controlled study, the experimental group consisted of 15 women aged 34-55 (mean age, 41.53 ± 6.98 years) with diagnosed multiple sclerosis who underwent a series of whole-body cryotherapy treatments. The first control group consisted of 20 women with diagnosed multiple sclerosis. This group had no intervention in the form of whole-body cryotherapy. The second control group consisted of 15 women aged 30-49 years (mean age, 38.47 ± 6.0 years) without neurological diseases and other chronic diseases who also underwent the whole-body cryotherapy treatment. For the analysis of the blood indices, venous blood was taken twice (first, on the day of initiation of whole-body cryotherapy treatments and, second, after a series of 20 cryotherapy treatments). The blood counts were determined using an ABX MICROS 60 hematological analyzer (USA). The LORCA analyzer (Laser-Optical Rotational Cell Analyzer, RR Mechatronics, the Netherlands) was used to study the aggregation and deformability of erythrocytes. The total protein serum measurement was performed using a Cobas 6000 analyzer, Roche and a Proteinogram-Minicap Sebia analyzer. Fibrinogen determinations were made using a Bio-Ksel, Chrom-7 camera. Statistically significant differences and changes after WBC in the levels of red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), elongation index, total extend of aggregation (AMP), and proteins (including fibrinogen) were observed. However, there was no significant effect of a series of 20 WBC treatments on changes in blood counts, rheology, and biochemistry in women with multiple sclerosis. Our results show that the use of WBC has a positive effect on the rheological properties of the blood of healthy women.
ABSTRACT
A i m: The aim of this study was to assess long-term outcomes and complications associated with conservative and operative treatment of distal radius fractures and to determine if restoration of radio- graphic parameters influences functional outcomes. I n t r o d u c t i o n: Distal radius fractures (DRFs) are common injuries associated with many complications. Numerous studies suggest that operative treatment with anatomic reduction and restoration of radiographic parameters leads to better functional outcomes than nonsurgical treatment.Materials and Methods: We enrolled 207 patients with isolated DRF (mean age 64 ± 17.9 years, women 150 (72.5%)) to our retrospective, single-center study (101 treated operatively, 106 treated non-operatively). There were no significant differences in sex, age, AO type fracture between study groups. After 3.9 ± 1.6 years (mean ± SD) clinical, functional and radiological assessment was conducted using Disabilities of the Arm, Shoulder and Hand (DASH), Patient Rated Wrist Evaluation (PRWE), 9-Hole Peg Test (9-HPT), grip and pinch strength tools. R e s u l t s: We found higher rates of malunion in nonoperative group (p <0.0001) and worse radiologic parameters such as volar tilt (p <0.0001), teardrop angle (p <0.0001) versus operative cohort. Nevertheless radiological parameters were not correlated with DASH and PRWE results. Moreover, patients aged 50 years and above treated operatively had similar functional outcomes (DASH, PRWE) to those treated nonoperatively. C o n c l u s i o n s: Restoration of anatomic and thus radiologic parameters of radius may not be obligatory to achieve satisfactory functional outcome in patients with DRF aged 50 years or above. Patient is the most important 'factor' in determining appropriate and successful treatment method of distal radius fractures.
Subject(s)
Radius Fractures , Aged , Aged, 80 and over , Female , Fracture Fixation, Internal , Humans , Middle Aged , Radiography , Radius Fractures/diagnostic imaging , Radius Fractures/therapy , Retrospective Studies , Treatment Outcome , Wrist Joint/diagnostic imagingABSTRACT
The aim of this work was to synthesize porous ceramic materials from the SiOC system by the sol-gel method and the subsequent pyrolysis. The usage of two types of precursors (siloxanes) was determined by Si/C ratio in starting materials. It allows us to control the size of the pores and specific surface area, which are crucial for the potential applications of the final product after thermal processing. Methyltrimethoxysilane and dimethyldiethoxysilane were mixed in three different molar ratios: 4:1, 2:1, and 1:1 to emphasize Si/C ratio impact on silicon oxycarbide glasses properties. Structure and microstructure were examined both for xerogels and obtained silicon oxycarbide materials. Brunauer-Emmett-Teller (BET) analysis was performed to confirm that obtained materials are porous and Si/C ratio in siloxanes precursors affects porosity and specific surface area. This kind of porous ceramics could be potentially applied as gas sensors in high temperatures, catalyst supports, filters, adsorbents, or advanced drug delivery systems.
ABSTRACT
Aluminum oxide is one of the most commonly used materials in the industry. It is used in the field of catalysis, refractories, and optics. Despite the fact that there are many techniques available, there is still a great challenge in obtaining a material with desired and designed properties. Nevertheless, there is a great flexibility in making customized alumina materials with desired physicochemical properties synthesized by sol-gel methods. This work consists in characterizing the physicochemical properties of sol-gel synthesized aluminum oxide using different sol-gel preparation routes. Three different sols were obtained by using organic precursors and underwent thermal treatment. The structure (Middle Infrared Spectroscopy, Diffused Reflectance Infrared Spectroscopy, X-ray Diffraction, Magic Angle Spinning Nuclear Magnetic Resonance) and microstructure (Scanning Electron Microscopy with Electron Dispersive Spectroscopy) tests of the materials were carried out. The specific surface area was determined by using the Brunauer-Emmett-Teller (BET) method. Thermal analysis was performed for all the powders, in order to analyze the specific temperature of materials transformation.
ABSTRACT
Silicon oxynitrides (SiOxNy) have many advantageous properties for modern ceramic applications that justify a development of their new and efficient preparation methods. In the paper, we show the possibility of preparing amorphous SiOxNy-based materials from selected liquid organosilicon compounds, methyltrimethoxysilane CH3Si(OCH3)3 and methyltriethoxysilane CH3Si(OC2H5)3, by a convenient spray pyrolysis method. The precursor mist is transported with an inert gas or a mixture of reactive gases through a preheated tube reactor to undergo complex decomposition changes, and the resulting powders are collected in the exhaust filter. The powders are produced at the tube at temperatures of 1200, 1400, and 1600 °C under various gas atmosphere conditions. In the first option, argon Ar gas is used for mist transportation and ammonia NH3 gas serves as a reactive medium, while in the second option nitrogen N2 is exclusively applied. Powder X-Ray Diffraction (XRD) results confirm the highly amorphous nature of all products except those made at 1600 °C in nitrogen. SEM examination shows the spheroidal particle morphology of powders, which is typical for this method. Fourier Transform Infrared (FT-IR) spectroscopy reveals the presence of Si-N and Si-O bonds in the powders prepared under Ar/NH3, whereas those produced under N2 additionally contain Si-C bonds. Raman spectroscopy measurements also support some turbostratic free carbon C in the products prepared under nitrogen. The directly determined O- and N-contents provide additional data linking the process conditions with specific powder composition, especially from the point of view of oxygen replacement in the Si-O moieties formed upon initial precursor decomposition reactions by nitrogen (from NH3 or N2) or carbon (from the carbonization of the organic groups).
ABSTRACT
OBJECTIVES: Medical students are more susceptible to depression than other students. Moreover, students with the symptoms of depression statistically more often abuse drugs and have suicidal thoughts and anxiety. The level of stress and the factors that lead to in among medical students at Polish universities have not yet been measured. The aim of this study was to translate to Polish and validate the Perceived Medical School Stress Instrument (PMSS-PL) and to measure the resulting version's psychometric abilities. MATERIALS AND METHODS: We validated the Polish translation of PMSS in accordance with the recommendations published by the Translation and Cultural Adaptation group of the Quality of Life Special Interest group of the International Society for Pharmacoeconomics and Outcomes Research. The Perceived Stress Scale (PSS-10) was used as an external test to validate the PMSS-PL questionnaire. A total of 430 undergraduate medical students at the Medical College of Jagiellonian University took part. RESULTS: The mean PMSS-PL score was 36.43 and it varied from 13 to 65. The mean PSS-10 was 21.35. The internal reliability, as indicated by Cronbach's alpha, was 0.803, which means there was internal reliability between PSS-10 and PMSS-PL. Moreover, all questions from PMSS-PL had a positive discrimination power, so each question correlated positively with the other questions in PMSS-PL. CONCLUSIONS: PMSS-PL may be used to psychometrically analyze the stress load on undergraduate medical students at Polish universities. The PMSS-PL may also be used as an external test for validating and calculating the reliability and accuracy of other psychometric instruments.