Influence of the Selected Physical Modifier on the Dynamical Behavior of the Polymer Composites Used in the Aviation Industry

In this research, an analysis of polymer composite with the matrix of L285-cured hardener H286 and six reinforcement layers of carbon fabric GG 280 T was provided. It involved a comparison of the dynamical behavior responses for three cases of composite structures in the context of the presence of the mass share modifier. The samples with the addition of a physical modifier with varying mass percentages were investigated by being subjected to dynamic tests with specific parameters, i.e., constant excitation amplitude and vibration frequency in the vicinity of the base resonance zone. The analysis allowed for indicating the relationship between the composition of the prepared composites and their dynamic response via stiffness characteristics. In addition, the investigation resulted in determining the range of harmful dynamical operating conditions, which may contribute to damage to the composite structures.     

Influence of Reaction Parameters on the Gelation of Silanised Linseed Oil

The subject of this work was to characterize the catalytic course of the linseed oil silylation reaction with vinyltrimethoxysilane (VTMOS), carried out under elevated pressure and temperature conditions, and an explanation of the reasons for rapid gelation of the reaction product. To explain and describe the process, analytical methods were used, i.e., ¹H and ¹³C NMR (nuclear magnetic resonance), GC-FID (gas chromatography coupled with flame ionisation detection), and GPC (gel permeation chromatography). Reaction products were monitored after 3, 6 and 12 h. The molar mass of the VTMOS-modified oil in only 3 h was comparable with the molar mass of the product obtained by conventional polymerisation. An increase in the reaction time resulted in further transformations resulting from the hydrolysis and condensation reactions taking place. In contrast to reactivity of soybean oil, the silanisation of linseed oil occurred much faster and without the need for cross-linking catalysts. The reason for the high reactivity of linseed oil to VTMOS and rapid gelation of the resulting product was primarily the amount of double bonds present in linseed oil and their high availability, in particular the double bond in the acid linolenic acid located at the C16 carbon.     

The Latest Achievements in the Construction of Influenza Virus Detection Aptasensors

Aptamers are short fragments of nucleic acids, DNA or RNA that have the ability to bind selected proteins with high specificity and affinity. These properties allow them to be used as an element of biosensors for the detection of specific proteins, including viral ones, which makes it possible to design valuable diagnostic tools. The influenza virus causes a huge number of human and animal deaths worldwide every year, and contributes to remarkable economic losses. In addition, in 2020, a new threat appeared—the SARS-Cov-2 pandemic. Both disease entities, especially in the initial stage of infection, are almost identical in terms of signs and symptoms. Therefore, a diagnostic solution is needed that will allow distinguishing between both pathogens, with high sensitivity and specificity; it should be cheap, quick and possible to use in the field, for example, in a doctor’s office. All the mentioned properties are met by aptasensors in which the detection elements are specific aptamers. We present here the latest developments in the construction of various types of aptasensors for the detection of influenza virus. Aptasensor operation is based on the measurement of changes in electric impedance, fluorescence or electric signal (impedimetric, fluorescence and electrochemical aptasensors, respectively); it allows both qualitative and quantitative determinations. The particularly high advancement for detecting of influenza virus concerns impedimetric aptasensors.     

Lithium disturbs homeostasis of essential microelements in erythrocytes of rats: Selenium as a protective agent?

Background

Selenium is an essential element which shows protective properties against diverse harmful factors. Lithium compounds are widely used in medicine, but, in spite of undoubted beneficial effects, treatment with these compounds may lead to severe side effects, including renal, gastrointestinal, neurological, endocrine and metabolic disorders. This study was aimed at evaluating the influence of selenium and/or lithium on lithium, iron, zinc and copper content in rats’ erythrocytes as well as estimate the action of additional selenium on lithium exposure effects.

The attractiveness of family medicine among Polish medical students

Background: In many developed countries tuning supply and demand of medical doctors is a continuous challenge to meet the ever changing needs of community and individual patients. The long study period for medical doctors creates the opportunity to observe the current career preferences of medical students and evolution in time.

Objectives: To investigate the career choices of Polish students in different stages of their medical education.

Methods: Medical students at five Polish medical universities were questioned about their career aspirations in the first, third and sixth year.

Results: A total of 2020 students were recruited for the survey. Among first year students 17% preferred family medicine as final career option, compared to 20% in the third year, and 30% in the sixth year (significant trend, P < 0.0001). In particular, female students prefer family medicine: 71% women versus 62% women in the group with a preference for a non-family medicine orientation (P = 0.008). Medical students rejecting a career as a family doctor stated that the impossibility to work in a hospital environment was the determining factor.

Conclusion: The opportunity for professional development seems to be an important determining factor in the choice of a medical specialty in Poland. The proportion of Polish students choosing family medicine increases during their progress in medical education, with one third of students interested in a career in family medicine by year six.     

Supporting mandibular resection with intraoperative navigation utilizing augmented reality technology – A proof of concept study

ObjectiveThe aim of this study was to compare the accuracy of simulated mandibular osteotomies performed with cutting guides and two different intraoperative navigation systems based on simple (sAR) and navigated (nAR) augmented reality technology.Material and methodsA total of 126 osteotomies were performed on 21 identical mandible models according to a prespecified virtual surgery plan. The data from postoperative computed tomography (CT) images were fused with preoperative CT scans to objectively compare the outcomes, i.e. angular deviations from the osteotomy trajectory (°) and displacement of two control points (mm).ResultsOsteotomies performed with cutting guides turned out to be the most accurate, with mean angular deviation of 4.94 ± 4.62° and mean control point displacement of 1.65 ± 0.88 mm. Mandibular osteotomies assisted with sAR and nAR were less accurate in terms of mean angular deviations (5.34 ± 3.67° and 7.14 ± 5.19°, respectively) and control point displacements (1.79 ± 0.94 mm and 2.41 ± 1.34 mm, respectively).ConclusionOur findings imply that in future, AR-based intraoperative navigation systems may find application in everyday clinical practice. Although AR technology still requires some improvements, it can already be used for presentation of digital navigation data, enhancing surgeon's awareness and hand-eye coordination during mandibular resection and reconstruction procedures.     

The Release of NSAIDs Such as Ibuprofen and Diclofenac from Magnetic Nanoparticles Coated with Dextran

Pharmaceutical Chemistry Journal - In this study, iron oxide (Fe3O4) nanoparticles were synthesized using the Massart co-precipitation method followed by surface coating with dextran. Next, coated...     

Development of Composite,Reinforced, Highly Drug-Loaded Pharmaceutical Printlets Manufactured by Selective Laser Sintering—In Search of Relevant Excipients for Pharmaceutical 3D Printing

3D printing by selective laser sintering (SLS) of high-dose drug delivery systems using pure brittle crystalline active pharmaceutical ingredients (API) is possible but impractical. Currently used pharmaceutical grade excipients, including polymers, are primarily designed for powder compression, ensuring good mechanical properties. Using these excipients for SLS usually leads to poor mechanical properties of printed tablets (printlets). Composite printlets consisting of sintered carbon-stained polyamide (PA12) and metronidazole (Met) were manufactured by SLS to overcome the issue. The printlets were characterized using DSC and IR spectroscopy together with an assessment of mechanical properties. Functional properties of the printlets, i.e., drug release in USP3 and USP4 apparatus together with flotation assessment, were evaluated. The printlets contained 80 to 90% of Met (therapeutic dose ca. 600 mg), had hardness above 40 N (comparable with compressed tablets) and were of good quality with internal porous structure, which assured flotation. The thermal stability of the composite material and the identity of its constituents were confirmed. Elastic PA12 mesh maintained the shape and structure of the printlets during drug dissolution and flotation. Laser speed and the addition of an osmotic agent in low content influenced drug release virtually not changing composition of the printlet; time to release 80% of Met varied from 0.5 to 5 h. Composite printlets consisting of elastic insoluble PA12 mesh filled with high content of crystalline Met were manufactured by 3D SLS printing. Dissolution modification by the addition of an osmotic agent was demonstrated. The study shows the need to define the requirements for excipients dedicated to 3D printing and to search for appropriate materials for this purpose.     

Influence of the Grain Size Distribution of the Limestone Additives on the Color Properties and Phase Composition of Sintered Ceramic Materials Based on Cream-Firing Clays

The study focused on determining color changes in materials made of cream-firing clays from the Opoczno region (Poland) due to the addition of calcium carbonate in the form of limestone. Moreover, the influence of the grain size distribution of this additive on the color properties of the materials and their phase composition was determined. Test samples were prepared using theplastic method and fired at four different temperatures: 1120, 1140, 1160 and 1180 °C. The color properties of the surface of ceramic materials were determined in CIE-Lab color space using a colorimeter. Quantitative phase analysis was performed using the Rietveld method. The research showed that the addition of calcium carbonate causes an increase in the yellow color factor and a decrease in the red color factor and the brightness of the material. Moreover, it was proven that the grain size distribution of the additive used significantly influences the phase composition of the materials, thus determining the values of physical properties and the color of the materials.