20 research outputs found

    Biomass waste fern leaves as a material for a sustainable method of activated carbon production for CO2 capture

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    In this work, we report the use of activated carbon synthesized from a sustainable material - fern leaves - as a sorbent for carbon dioxide capture applications. The resource-friendly technology for activated carbon production was applied and described. The activated carbons were prepared by chemical and physical activation and carbonization at the same time at the temperature range of 500–900 \ub0C. This method reduces energy consumption and resources. KOH and CO2 were used as activating agents. The evaluation of the CO2 adsorption ability of the activated carbon was supported by different methods including: elemental analysis using X-ray fluorescence spectroscopy, ash content, surface area and porosity measurements, Raman spectroscopy, X-ray spectroscopy and scanning electron microscopy. Results indicated that the optimum temperature of the synthesis was 700 \ub0C. The highest achieved adsorption of CO2 was equal to 6.77 mmol/g and 3.58 mmol/g at 0 \ub0C and 25 \ub0C, respectively. The activated carbons synthesized from fern leaves showed high CO2 adsorption and selectivity. Moreover, the abundance and low cost of fern leaves make them very promising carbon sources for CO2 sorbents production

    Evaluation of carbetocin (Pabal) efficacy in the prevention of the postpartum hemorrhage in women after cesarean section – preliminary report

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    Abstract Objectives: The aim of this study was to evaluate the efficacy of carbetocin in prevention of PPH in women after cesarean section. Material and Methods: We enrolled 60 patients who had undergone cesarean section in tertiary referential center, Department of Perinatology, Medical University of Lodz, Poland, between January and June 2008. Each patient obtained a single 100μg dose of carbetocin intravenously during cesarean section, immediately after the delivery of the baby and prior to the delivery of the placenta . We evaluated postoperative blood parameters in 2 and 12 hours after the operation, the proportion of patients requiring additional uterotonic agents and adverse events in the whole population and in the group of women with high risk of PPH. Results: 58.1% of patients underwent emergency and 41.3% elective cesarean section delivery. The risk factor of PPH was identified in 38 women (63.3%). The results of this study indicate that carbetocin produces rapid and longlasting uterine tone. A small drop in mean hemoglobin and hematocrit levels 2 and 12 hours after the operation was observed. 15% of patients required the use of additional uterotonic agents. In the group of women with high risk of PPH, carbetocin appeared to be effective in 79% of the patients. Only 11.4% of patients had minor adverse events. Conclusions: Carbetocin appears to be an effective new drug in the prevention of postpartum hemorrhage, not only among women undergoing cesarean section but also in the group of women with PPH risk factors

    Costs of the use of carbetocin in the prevention of uterine atony following delivery of the infant by Caesarean section — retrospective multicenter study

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    Objectives: The aim of this study was to compare the costs of using carbetocin in the prevention of uterine atony following delivery of the infant by Cesarean section (C-section) under epidural or spinal anesthesia with standard methods of prevention (SMP). Material and methods: This retrospective multicenter study was based on data from three medical centers. A questionnaire was developed to gather patient records on consumption and costs of resources related to C-section, prevention of uterine atony and postpartum hemorrhage (PPH) treatment. Six subpopulations were considered, depending on patient characteristics. The analysis covered two perspectives: that of the hospital and of the public payer. Results: The subpopulations were homogenous, which was a premise for pooling the data. The use of carbetocin in the prevention of uterine atony following Cesarean section generates savings for hospital in comparison with SMP (oxytocin) in 5 of 6 subpopulations. The biggest savings were observed amongst patients who experienced severe PPH and reached 2.6–6.2 thousand PLN per patient. Costs of services related to C-section borne by the hospitals were higher than the refund received from a public payer. The greatest underestimation reached 12.1 thousand PLN per patient. Nevertheless, loss generated by this underfunding was lower in carbetocin versus oxytocin group. Conclusions: The use of carbetocin instead of SMP gives hospitals an opportunity to make savings as well as to reduce losses resulting from the underfunding of the services provided by the National Health Fund

    Recommendations of the Polish Medical Society of Radiology and the Polish Society of Neurology for the routinely used magnetic resonance imaging protocol in patients with multiple sclerosis

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    Magnetic resonance imaging (MRI) is a widely used method for the diagnosis of multiple sclerosis (MS) that is essential for the detection and follow-up of the disease. The Polish Medical Society of Radiology (PLTR) and the Polish Society of Neurology (PTN) present the second version of the recommendations for examinations routinely conducted in magnetic resonance imaging departments in patients with MS, which include new data and practical comments for electroradiology technicians and radiologists. The recommended protocol aims to improve the MRI procedure and, most importantly, to standardise the method of conducting scans in all MRI departments. This is crucial for the initial diagnostics that are necessary to establish a diagnosis as well as monitor patients with MS, which directly translates into significant clinical decisions. MS is a chronic idiopathic inflammatory demyelinating disease of the central nervous system (CNS), the aetiology of which is still unknown. The nature of the disease lies in the CNS destruction process disseminated in time and space. MRI detects focal lesions in the white and grey matter with high sensitivity (with significantly less specificity in the latter). It is also the best tool to assess brain atrophy in patients with MS in terms of grey matter volume and white matter volume as well as local atrophy (by measuring the volume of thalamus, corpus callosum, subcortical nuclei, hippocampus) as parameters that correlate with disability progression and cognitive dysfunctions. Progress in magnetic resonance techniques, as well as the abilities of postprocessing the obtained data, has become the basis for the dynamic development of computer programs that allow for a more repeatable assessment of brain atrophy in both cross-sectional and longitudinal studies. MRI is unquestionably the best diagnostic tool used to follow up the course of the disease and to treat patients with MS. However, to diagnose and follow up the patients with MS on the basis of MRI in accordance with the latest standards, an MRI study must meet certain quality criteria, which are the subject of this paper

    Recommendations of the Polish Medical Society of Radiology and the Polish Society of Neurology for a protocol concerning routinely used magnetic resonance imaging in patients with multiple sclerosis

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    Magnetic resonance imaging (MRI) is a widely used method for the diagnosis of multiple sclerosis that is essential for the detection and follow-up of the disease.Objective: The Polish Medical Society of Radiology (PLTR) and the Polish Society of Neurology (PTN) present the second version of their recommendations for investigations routinely conducted in magnetic resonance imaging departments in patients with multiple sclerosis. This version includes new data and practical comments for electroradiology technologists and radiologists. The recommended protocol aims to improve the MRI procedure and, most importantly, to standardise the method of conducting scans in all MRI departments. This is crucial for the initial diagnostics necessary for establishing a diagnosis, as well as for MS patient monitoring, which directly translates into significant clinical decisions.Introduction: Multiple sclerosis (MS) is a chronic immune mediated inflammatory demyelinating disease of the central nervous system (CNS), the aetiology of which is still unknown. The nature of the disease lies in a CNS destruction process disseminated in time (DIT) and space (DIS). MRI detects focal lesions in the white and grey matter with high sensitivity (although with significantly lower specificity in the latter). It is also the best tool to assess brain atrophy in patients with MS in terms of grey matter volume (GMV) and white matter volume (WMV) as well as local atrophy (by measuring the volume of thalamus, corpus callosum, subcortical nuclei, and hippocampus) as parameters that correlate with disability progression and cognitive dysfunctions. Progress in MR techniques, as well as advances in postprocessing the obtained data, has driven the dynamic development of computer programs that allow for a more repeatable assessment of brain atrophy in both cross-sectional and longitudinal studies. MR imaging is unquestionably the best diagnostic tool available to follow up the course of the disease and support clinicians in choosing the most appropriate treatment strategy for their MS patient. However, to diagnose and follow up MS patients on the basis of MRI in accordance with the latest standards, the MRI study must adhere to certain quality criteria. Such criteria are the subject of this paper

    Nanoshaped Cerium Oxide with Nickel as a Non-Noble Metal Catalyst for CO<sub>2</sub> Thermochemical Reactions

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    Four different nanoshapes of cerium dioxide have been prepared (polycrystals, rods, cubes, and octahedra) and have been decorated with different metals (Ru, Pd, Au, Pt, Cu, and Ni) by incipient wetness impregnation (IWI) and ball milling (BM) methods. After an initial analysis based on oxygen consumption from CO2 pulse chemisorption, Ni-like metal, and two forms of CeO2 cubes and rods were selected for further research. Catalysts were characterized using the Brunauer-Emmett-Teller formula (BET), X-ray spectroscopy (XRD), Raman spectroscopy, scanning electron microscopy (SEM), UV–visible spectrophotometry (UV-Vis), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (H2-TPR) and CO2 pulse chemisorption, and used to reduce of CO2 into CO (CO2 splitting). Adding metals to cerium dioxide enhanced the ability of CeO2 to release oxygen and concomitant reactivity toward the reduction of CO2. The effect of the metal precursor and concentration were evaluated. The highest CO2 splitting value was achieved for 2% Ni/CeO2-rods prepared by ball milling using Ni nitrate (412 µmol/gcat) and the H2 consumption (453.2 µmol/gcat) confirms the good redox ability of this catalyst

    Application of isotherms models and error functions in activated carbon CO2 sorption processes

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    This work is concerned with the calculations using eight different isotherm models (Langmuir, Freundlich, Halsey, Temkin, Toth, Sips, Radke-Prausnitz, and Redlich-Peterson) to fit the experimental isotherm data of CO2 on activated carbon (AC). Moreover, systematic and comprehensive modeling of non-linearized isotherms was performed by developing an algorithm for determining their parameters and analyzing seven error functions. To determine the best-fitted isotherm model and error function, we used the sum of normalized errors (SNE) procedure. The modeling results obtained showed that the Redlich-Peterson, Radke-Prausnitz, and Toth isotherm models are best suited to the empirical data, with relatively high R2 determination coefficients. Finally, the SNE method allowed the selection of the chi-square test (χ2) and the HYBRID error as universal indicators in nonlinear regression to select the set of optimized isotherm parameters. The interpretation of the assumptions of the isotherm models, which featured a strong correlation with the experimental data, allowed a conclusion to be drawn about the sub-monolayer adsorption mechanism on the heterogeneous surface of the AC. The acquired modeling findings are expected to establish a certain theoretical foundation for the characterization of CO2 adsorption equilibrium studies at the interface between porous solid materials and gases

    Activated carbons—preparation, characterization and their application in CO2 capture: A review

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    In this paper, we provide a comprehensive review of the latest research trends in terms of the preparation, and characteristics of activated carbons regarding CO2 adsorption applications, with a special focus on future investigation paths. The reported current research trends are primarily closely related to the synthesis conditions (carbonization and physical or chemical activation process), to develop the microporosity and surface area, which are the most important factors affecting the effectiveness of adsorption. Furthermore, we emphasized the importance of regeneration techniques as a factor determining the actual technological and economic suitability of a given material for CO2 capture application. Consequently, this work provides a summary and potential directions for the development of activated carbons (AC). We attempt to create a thorough theoretical foundation for activated carbons while also focusing on identifying and specific statements of the most relevant ongoing research scope that might be advantageous to progress and pursue in the coming years

    An innovative and environmentally friendly bioorganic synthesis of activated carbon based on olive stones and its potential application for CO2 capture

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    This work presents an innovative, fully environmentally friendly method of obtaining bioorganic activated carbon based on olive stones by applying banana plant extract as an activating agent. The activated carbon prepared in this way was compared with activated carbons prepared by chemical activation using potassium hydroxide (KOH) and phosphoric acid (H3PO4). The obtained results of physicochemical characterization were comparable to the currently commonly obtained activated carbons. For the novel activated carbon, the specific surface area was equal to 915 m2/g, and the pore area was 0.495 cm3/g. The CO2 adsorption capacity of the newly obtained activated carbon was also tested and it was 6.32 mmol/g and 4.33 mmol/g for 0 \ub0C and 30 \ub0C, respectively. This material has a high selectivity equal to 161.1 and stability after the 50th adsorption-desorption cycles. The material prepared in this way creates new possibilities for obtaining high-quality activated carbon and it does away with the requirement for using any hazardous inorganic activating agent like acids or bases, which makes it completely harmless to the environment

    Computer Analysis of the Effect of Activation Temperature on the Microporous Structure Development of Activated Carbon Derived from Common Polypody

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    This paper presents the results of a computer analysis of the effect of activation process temperature on the development of the microporous structure of activated carbon derived from the leaves of common polypody (Polypodium vulgare) via chemical activation with phosphoric acid (H3PO4) at activation temperatures of 700, 800, and 900 °C. An unconventional approach to porous structure analysis, using the new numerical clustering-based adsorption analysis (LBET) method together with the implemented unique gas state equation, was used in this study. The LBET method is based on unique mathematical models that take into account, in addition to surface heterogeneity, the possibility of molecule clusters branching and the geometric and energy limitations of adsorbate cluster formation. It enabled us to determine a set of parameters comprehensively and reliably describing the porous structure of carbon material on the basis of the determined adsorption isotherm. Porous structure analyses using the LBET method were based on nitrogen (N2), carbon dioxide (CO2), and methane (CH4) adsorption isotherms determined for individual activated carbon. The analyses carried out showed the highest CO2 adsorption capacity for activated carbon obtained was at an activation temperature of 900 °C, a value only slightly higher than that obtained for activated carbon prepared at 700 °C, but the values of geometrical parameters determined for these activated carbons showed significant differences. The results of the analyses obtained with the LBET method were also compared with the results of iodine number analysis and the results obtained with the Brunauer–Emmett–Teller (BET), Dubinin–Radushkevich (DR), and quenched solid density functional theory (QSDFT) methods, demonstrating their complementarity
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