Structure and properties of slow-resorbing nanofibers obtained by (co-axial) electrospinning as tissue scaffolds in regenerative medicine

With the rapid advancement of regenerative medicine technologies, there is an urgent need for the development of new, cell-friendly techniques for obtaining nanofibers—the raw material for an artificial extracellular matrix production. We investigated the structure and properties of PCL10 nanofibers, PCL5/PCL10 core-shell type nanofibers, as well as PCL5/PCLAg nanofibres prepared by electrospinning. For the production of the fiber variants, a 5–10% solution of polycaprolactone (PCL) (Mw = 70,000–90,000), dissolved in a mixture of formic acid and acetic acid at a ratio of 70:30 m/m was used. In order to obtain fibers containing PCLAg 1% of silver nanoparticles was added. The electrospin was conducted using the above-described solutions at the electrostatic field. The subsequent bio-analysis shows that synthesis of core-shell nanofibers PCL5/PCL10, and the silver-doped variant nanofiber core shell PCL5/PCLAg, by using organic acids as solvents, is a robust technique. Furthermore, the incorporation of silver nanoparticles into PCL5/PCLAg makes such nanofibers toxic to model microbes without compromising its biocompatibility. Nanofibers obtained such way may then be used in regenerative medicine, for the preparation of extracellular scaffolds: (i) for controlled bone regeneration due to the long decay time of the PCL, (ii) as bioscaffolds for generation of other types of artificial tissues, (iii) and as carriers of nanocapsules for local drug delivery. Furthermore, the used solvents are significantly less toxic than the solvents for polycaprolactone currently commonly used in electrospin, like for example chloroform (CHCl3), methanol (CH3OH), dimethylformamide (C3H7NO) or tetrahydrofuran (C4H8O), hence the presented here electrospin technique may allow for the production of multilayer nanofibres more suitable for the use in medical field

Rapid continuous microwave-assisted synthesis of silver nanoparticles to achieve very high productivity and full yield : from mechanistic study to optimal fabrication strategy

Systematic studies of silver nanoparticle synthesis in a continuous-flow single-mode microwave reactor using polyol process were performed, revealing that the synthesis is exceptionally effective to give very small metal particles at full reaction yield and very high productivity. Inlet concentration of silver nitrate or silver acetate, applied as metal precursors, varied between 10 and 50 mM, and flow rates ranged from 0.635 to 2.5 dm3/h, to give 3–24 s reaction time. Owing to its much higher reactivity, silver acetate was shown to be far superior substrate for the synthesis of small (10–20 nm) spherical silver nanoparticles within a few seconds. Its restricted solubility in ethylene glycol, applied as the solvent and reducing agent, appeared to be vital for effective separation of the stage of particle growth from its nucleation to enable rapid synthesis of small particles in a highly loaded system. This was not possible to obtain using silver nitrate. All the observations could perfectly be explained by a classical LaMer–Dinegar model of NPs’ formation, but taking into account also nonisothermal character of the continuous-flow process and acetate dissolution in the reaction system. The performed studies indicate an optimal strategy for the high-yield fabrication of metal particles using polyol method

FRICTIONAL PROPERTIES OF SELECTED SEEDS

K e y w o r d s: physical attributes, coefficient of external friction, relation. A b s t r a c t The thickness, width, length and weight of five seed species (buckwheat, vetch, pea, lupine and faba bean) and their external friction angle were determined on two types of surfaces -steel and rubber. The experiment was performed with the use of a an inclined plane with an adjustable angle of inclination that measures the angle of external friction and the time taken by seeds to travel a given distance, which supports the determination of the coefficient of kinetic friction. The measured parameters were used to calculate arithmetic and geometric mean diameter, aspect ratio and sphericity index. The dimensions, weight and the calculated indicators of the examined seeds did not significantly affect their coefficients of static and kinetic friction or their coefficients of rolling resistance and rolling friction. The studied parameters were largely influenced by the type of friction surface, and significantly lower average values were reported for steel than rubber. In the studied seed species, the static friction coefficient was determined in the range of 0.187 to 0.582, kinetic friction coefficient -0.134 to 0.479, rolling resistance coefficient -0.148 to 0.529 and rolling friction coefficient -0.29 to 1.80 mm. Symbols: D a -arithmetic mean diameter, mm, D g -geometric mean diameter, mm, m -seed weight, mg f 1 , f 2 -coefficient of rolling friction of seeds on steel and rubber, respectively, mm, r -radius of a rolling seed, mm, R -aspect ratio, %, S -travel distance of the particle, m, t -time required by the particle to travel distance, s, T, W, L -seeds thickness, width and length, mm, x, SD -average value and standard deviation of trait, x min , x max -minimum and maximum value of trait, α -angle of external friction of seeds, o , α s1 , α s2 -angle of static friction of seeds on steel and rubber, respectively, o , α t1 , α t2 -angle of rolling friction of seeds on steel and rubber, respectively, o , μ -coefficient of external friction of seeds, Correspondence: Zdzisław Kaliniewicz, Katedra Maszyn Roboczych i Metodologii Badań, Uniwersytet Warmińsko-Mazurski, ul. Oczapowskiego 11/B112, 10-719 Olsztyn, phone: +48 89 523 39 34, e-mail: [email protected] μ k1 , μ k2 -coefficient of kinetic friction of seeds on steel and rubber, respectively, μ s1 , μ s2 -coefficient of static friction of seeds on steel and rubber, respectively, μ t1 , μ t2 -coefficient of rolling resistance of seeds on steel and rubber, respectively. Φ -sphericity index, %

Can selected physiotherapeutic techniques really help in treating back pain and improving the quality of life of advanced cancer patients: a randomised controlled study

Background: The available literature lacks studies using the KinesioTaping (KT) method and the hold-relax (HR) technique in working with advanced cancer patients. Patients and methods: The study involved 72 patients (38 women and 34 men), diagnosed with advanced cancer. Patients were randomly assigned either to KT group (exercise programme and KT), HR group (exercise programme and the HR technique of the proprioceptive neuromuscular facilitation — PNF method) or C group (a control group, exercise programme). To assess selected parameters the Numerical Rating Scale (NRS) scale and Edmonton Symptom Assessment System — revised (ESAS-r) were used. The physiotherapeutic programme lasted three weeks and took place 5 days a week for 30 minutes within each group. Additionally, in the KT group, kinesio tapes were applied on the paraspinal muscles of the lumbar spine. In the HR group the therapy with the Hold–Relax technique was applied. Results: There was a statistically significant decrease in pain in all groups and improvement in the quality of life in patients from both experimental groups. Those changes were significantly greater in the KT group than in both the C group and the HR group. Conclusions: Both KT and HR techniques of the PNF method are effective in reducing pain and improving the quality of life in the examined advanced cancer patients, however KT has a stronger impact

Acorn: A grid computing system for constraint based modeling and visualization of the genome scale metabolic reaction networks via a web interface

Constraint-based approaches facilitate the prediction of cellular metabolic capabilities, based, in turn on predictions of the repertoire of enzymes encoded in the genome. Recently, genome annotations have been used to reconstruct genome scale metabolic reaction networks for numerous species, including Homo sapiens, which allow simulations that provide valuable insights into topics, including predictions of gene essentiality of pathogens, interpretation of genetic polymorphism in metabolic disease syndromes and suggestions for novel approaches to microbial metabolic engineering. These constraint-based simulations are being integrated with the functional genomics portals, an activity that requires efficient implementation of the constraint-based simulations in the web-based environment

Lead shielding efficiency from the gamma background measurements in the salt cavern of the Polkowice–Sieroszowice copper mine

The studies of lead shielding efficiency from the gamma background measurements were performed in the salt cavern of the copper mine - a site considered for an underground laboratory. Within the energy range of 50–2700 keV, the measured gamma-ray count rates normalized to the mass of the high-purity detectors germanium crystal are 5.93 and 6.32 s−1kg−1 for the used low-background and portable spectrometers, respectively. The gamma-ray flux of 0.124 (2) cm−2s−1 connected with the natural radioisotopes was observed by the portable HPGe, including 0.026 (1) cm−2s−1 contribution of radon decay products, whereas the photon flux at the spectrum continuum was 0.18 (5) cm−2s−1

Państwo i społeczeństwo wobec chaosu przestrzennego - źródła i działania: Dyskusja redakcyjna

The following debate took place on March 22, 2019 at the Warsaw School of Economics. The content of the Study on Spatial Chaos report provided the framework for the discussion. Its authors estimated the cost of spatial chaos at PLN 84.3 billion per year. They indicated the main mechanisms leading to the occurrence of this phenomenon

Społeczne funkcje sztuki

Z wprowadzenia: "Ilekroć będziemy mówić o państwie, gospodarstwie, społeczeństwie - tylekroć będziemy również mówić o sztuce. Współcześnie, na progu nowego wieku, nieograniczone wręcz możliwości budowania scenerii naszego życia społecznego z udziałem sztuk plastycznych i architektury sprawiają, iż nieustannie rośnie liczba tematów z nimi związanych wartych omówienia. Społeczne funkcje sztuki - sens naszych rozważań - ujęliśmy w dwa bloki tematyczne: a mianowicie sztuki projektowania i rolę sztuk pięknych w życiu społecznym."(...