Fractal analysis and microstructure development PVDF based multifunctional material

Polyvinylidene fluoride (PVDF) is a novel gel polymer electrolyte alternative which can reduce the risk of irreversible failure in lithium-ion batteries (LIB) [1]. PVDF matrix structures which exhibit inter-crosslinking networks have previously demonstrated favorable thermal and mechanical properties for LIB applications [2]. PVDF based multifunctional material is attracting a great scientific interest due to its excellent piezoelectric, pyroelectric and ferroelectric properties. Such as, its properties strongly depend on synthesis procedures and obtained microstructures. In this research, porous structure and cross-linking patterns of PVDF were prepared by electrospinning method and it has been found that these microstructures can have fractal structure. Fractal analysis can be used as a powerful tool for describing structural and functional properties of these this material. Because of that, in this research we have used different fractal methods for the reconstructions of various PVDF microstructure morphologies. Fractal analysis has been performed by using scanning electron microscope micrographs and computational modeling tools. Theory of Iterated Function Systems and Voronoi tessellation, have been used for modeling PVDF porous structures. A Python algorithm was created to determine the distribution of pore areas in SEM micrographs. Algorithm’s distribution of calculated pore surface areas were compared with measured pore surface areas and fractal reconstructions of different morphologies and their connection with functional properties were analyzed

Fractal analysis and microstructure development of BaTiO3 and PVDF based multifunctional materials

Barium titanate (BaTiO3) and polyvinylidene fluoride (PVDF) based multifunctional materials are attracting a great scientific interest due to their excellent piezoelectric, pyroelectric and ferroelectric properties. These materials undergo controlled transformations through physical interactions and respond to environmental stimuli, such as temperature, pressure, electric and magnetic fields. Their properties strongly depend on synthesis procedures and obtained microstructures. This include intergranular contact surfaces of BaTiO3 based materials, as well as, porous structure and cross-linking patterns of PVDF prepared by electrospinning. It has been found that these microstructures can have fractal structure and that the fractal analysis can be used as a powerful tool for describing structural and functional properties of these materials. Having this in mind, in this research we have used different fractal methods for the reconstructions of various BaTiO3 and PVDF microstructure morphologies. Fractal analysis has been performed by using scanning electron microscope micrographs and computational modeling tools. Fractal dimension of irregular morphologies which exhibit fractal regularity were determined by using box-counting method. This method enables the analysis of self-similar microstructure morphologies by quantifying the rate at which an object's geometrical details develop at increasingly fine scales. Theory of Iterated Function Systems and Voronoi tessellation, have been used for modeling BaTiO3 random microstructures and PVDF porous structures. A python algorithm was created to determine the distribution of pore areas in SEM micrographs. Algorithm’s distribution of calculated pore surface areas was compared with measured pore surface areas and fractal reconstructions of different morphologies and their connection with functional properties were analyzed

Lead Free Polymer Composites for Radiation Shielding

Radiation shielding is a crucial precautionary measure in decreasing the dose of exposure medical personnel experience. The physical dimensions of these shields, specifically thickness and shape, are dependent on the type of radiation, energy and specific radioactivity. Currently, the most common radiation shielding equipment is made of lead, tungsten or uranium. Although these heavy metals have favorable shielding properties against ionizing radiation, protective garments such as lead aprons are heavy to wear and can pose significant health risks. Taking this into account, the primary goal of this study is to understand the radiation shielding properties of lead-free polymer geopolymer-polyurethane based composites. The geopolymer was synthesized using an 80%-20% mixture of fly ash and a bio-polyol substrate which was subsequently homogenized using MDI44. As a result, 6 samples of the geopolymer-polyurethane based composites were fabricated of which 5 were 90%-10% compositions between the mixture and varying concentrations of BaSO4 and Bi2O3 respectively. The last sample consisted of the pure fly ash/bio-polyol mixture. XRF and ICP analysis was used to chemically characterize the fly ash. The composite structures were analyzed using XRD, while the microstructural morphology was investigated using SEM techniques. Utilizing an energy-dispersive x-ray spectrometer (EDS), elemental abundance and agglomerating behavior was analyzed for each composite variant. The X-ray attenuation measurements pointed out that the obtained composites have the potential for a design of lead-free protective clothing against X-ray shielding in medical applications

Lead Free Polymer Composites for Radiation Shielding

Radiation shielding is a crucial precautionary measure in decreasing the dose of exposure medical personnel experience. The physical dimensions of these shields, specifically thickness and shape, are dependent on the type of radiation, energy and specific radioactivity. Currently, the most common radiation shielding equipment is made of lead, tungsten or uranium. Although these heavy metals have favorable shielding properties against ionizing radiation, protective garments such as lead aprons are heavy to wear and can pose significant health risks. Taking this into account, the primary goal of this study is to understand the radiation shielding properties of lead-free polymer geopolymer-polyurethane based composites. The geopolymer was synthesized using an 80%-20% mixture of fly ash and a bio-polyol substrate which was subsequently homogenized using MDI44. As a result, 6 samples of the geopolymer-polyurethane based composites were fabricated of which 5 were 90%-10% compositions between the mixture and varying concentrations of BaSO4 and Bi2O3 respectively. The last sample consisted of the pure fly ash/bio-polyol mixture. XRF and ICP analysis was used to chemically characterize the fly ash. The composite structures were analyzed using XRD, while the microstructural morphology was investigated using SEM techniques. Utilizing an energy-dispersive x-ray spectrometer (EDS), elemental abundance and agglomerating behavior was analyzed for each composite variant. The X-ray attenuation measurements pointed out that the obtained composites have the potential for a design of lead-free protective clothing against X-ray shielding in medical applications

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

After-Hours Versus Office-Hours Dental Injuries in Children: Does Timing Influence Outcome?

Aim. The aim of this study was to analyze the outcomes and factors associated with after-hours dental trauma. Methods. Study sample consisted of 1762 permanent teeth injuries in children, gender and age matched with office-hours injuries. Epidemiological and clinical data were collected from 4 university dental trauma centers. Results. During median follow-up time of 4.3 years, complications have occurred in 14.5% of injured teeth. Age, type, and degree of tissue injury and after-hours time of injury were significantly associated with complications. Unfavorable outcomes were 34% more likely in the after-hours group compared with office-hours. Urgent treatment was significantly delayed in after-hours group with a delay of more than 3 hours in 90.5% versus 38.9% in the office-hours group. Multivariate regression model showed that after-hours time of injury was significant predictor of complications. Conclusion. Delayed urgent treatment was one of the main factors associated with unfavorable outcome of after-hours injuries

Onečišćenje rijeke Save u Srbiji teškim metalima i bakterijama

The aim of this study was to establish microbial and heavy metal pollution of the Sava River at three locations close to industry and urban areas (Šabac, Obrenovac, Beograd) in Serbia. Heavy metal analysis included Cu, Zn, Pb, and Cd in the river water and sediment samples. Using the microbiological analysis we tried to establish the effectiveness of total coliforms, faecal coliforms and Escherichia coli in detecting pollution of surface waters. We found that E. coli levels steadily increased downstream from Šabac (location 1; 2100 MPN per 100 mL) to Belgrade (location 3; 10000 MPN per 100 mL). To prevent bacterial contamination, it is necessary to reduce the discharge of wastewater with faecal matters near highly populated towns. Heavy metal levels in sediments correlated with those in the river water. Fluctuations attributed mainly to anthropogenic sources were not high. These results point to acceptable anthropogenic contribution to heavy metal content in the Sava River and to low environmental risk.Ispitivani su mikrobiološki parametri i teški metali u rijeci Savi na tri lokacije u blizini industrijskih i urbanih centara (Šabac, Obrenovac, Beograd). Analiza je obuhvatila parametre kvalitete: teške metale – Cu, Zn, Pb i Cd u riječnoj vodi i sedimentu te bakterije i patogene bakterije u riječnoj vodi. Radi utvrđivanja bakterijske kontaminacije površinskih voda testirani su koliform Escherichia coli i fekalni koliformi. Brojnost E. coli povećava se od lokacije 1 prema ušću Save od 2100 do 10000 u 100 mL NVB (najvjerojatniji broj). Nađen je velik broj biološki aktivnih mikroorganizama i bakterija. Koncentracija teških metala u sedimentu u korelaciji je s njihovom koncentracijom u riječnoj vodi ako se izrazi s pomoću koefi cijenta distribucije Kd (dm3 kg-1) između čvrste i tekuće faze. Predložen je postupak za procjenu toksičnosti teških metala