Anionically stabilized cellulose nanofibrils through succinylation pretreatment in urea–lithium chloride deep eutectic solvent

Abstract Deep eutectic solvents (DESs) are green chemicals that have the potential to replace traditional solvents in chemical reactions. In this study, urea–LiCl DES was used successfully as a reaction medium in the anionic functionalization of wood cellulose with succinic anhydride. The effects of reaction temperature and time on the carboxyl content and yield were evaluated. The analyses of the degree of polymerization and crystallinity revealed that the DES was a nondegrading and nondissolving reaction medium. Three samples with the highest carboxyl contents were further nanofibrillated with a microfluidizer to diameters of 2–7 nm, as observed by atomic force microscopy. Samples treated at 70–80 °C for 2 h gave the best outcome and resulted in highly viscose and transparent gels. The sample treated at 90 °C contained larger nanoparticles and larger aggregates owing to the occurrence of possible side reactions but resulted in better thermal stability

Experiences of remote teaching, technological pedagogical competencies and workload of teachers in northern Finland during the COVID-19 pandemic

Abstract In this study, we examine the experiences of teachers, particularly in relation to their remote teaching competencies, in the county of Lapland, North Finland, during the COVID-19 pandemic, as they face new pedagogical challenges in remote teaching. To identify the teachers’ competency needs in remote teaching, the study uses questionnaire data (N=164) collected from primary, secondary and upper secondary school teachers. The results of the systematic representative survey study are analysed using the technological pedagogical content knowledge (TPACK) model to investigate the preconditions for and challenges in implementing remote teaching in terms of teachers’ competencies. The participants’ responses indicate that different municipalities prepared for remote teaching and learning in quite diverse ways. Some municipalities lacked the necessary tools for remote learning, and the workload increase and job satisfaction experienced by teachers were related to the digital tools provided by their employers. The development of teachers’ diverse competencies is pivotal in teacher education and in-service teacher training so that they can acquire the ability to take initiative and function well in diverse and changing educational contexts. This study outlines the dimensions of teachers’ technological pedagogical competencies that were further developed from the TPACK framework

Pohjois-Suomen opettajien kokemuksia etäopetuksesta, teknologis-pedagogisesta osaamisesta sekä työn kuormittavuudesta COVID-19 pandemian aikana

Tiivistelmä Tässä artikkelissa tarkastelemme Lapin alueen opettajien etäopetukseen liittyviä kokemuksia COVID-19 -pandemian aikana. Opettajien etäopetuksen osaamistarpeiden tunnistamiseksi tutkimuksessa hyödynnetään kyselyaineistoa (N=164), joka on kerätty perusasteen ja toisen asteen opettajilta aikana, jolloin opettajat kohtasivat uusia pedagogisia haasteita etäopetukseen liittyen. Tutkimuksen tuloksia reflektoidaan teknologis-pedagogis-sisällöllisen tietämyksen mallin (TPACK) valossa. Tavoitteena on selvittää etäopetuksen toteuttamisen edellytyksiä ja haasteita opettajien osaamisen kannalta. Opettajien vastauksista voidaan päätellä, että kunnat olivat varautuneet etäopetukseen varsin eri tavoin. Joistakin kunnista etäopetuksen mahdollistavat työvälineet puuttuivat kokonaan. Opettajien työmäärän lisääntyminen ja heidän kokema työtyytyväisyys olivat yhteydessä käytössä olleisiin työnantajan antamiin digitaalisiin työvälineisiin. Opettajan perus- ja täydennyskoulutuksessa tulisi kiinnittää huomiota opettajien monipuolisen teknologis-pedagogista osaamisen kehittämiseen, jotta opettajat pystyvät toimimaan aktiivisesti erilaisissa muuttuvissa opetus- ja oppimiskonteksteissa. Tutkimus selventää opettajien teknologis-pedagogisen osaamisen ulottuvuuksia, joita kehitettiin edelleen TPACK-mallin pohjalta

Rapid uptake of pharmaceutical salbutamol from aqueous solutions with anionic cellulose nanofibrils:the importance of pH and colloidal stability in the interaction with ionizable pollutants

Abstract Micropollutants escaping conventional wastewater treatment processes pose a threat to biota and the environment. Amongst micropollutants, small and ionizable organic compounds are particularly challenging, since their removal depends significantly on prevailing conditions. In this study, anionic cellulose nanofibrils (CNFs) were shown to perform as promising adsorbents for an ionizable pharmaceutical, salbutamol. The adsorbents were produced from wood cellulose through succinylation pretreatment in urea-LiCl deep eutectic solvent (DES), followed by a nanofibrillation procedure. The impact of pH, contact time, salbutamol concentration, and adsorbent dose on salbutamol uptake were investigated in batch adsorption studies. Based on the results, the chemical modification of cellulose significantly enhanced the adsorption of salbutamol. The adsorption efficiency was mainly dependent on the charge and colloidal stability of the anionic nanofibril suspension rather than the charge of salbutamol, because the adsorption was considerably improved at pH > 7 due to the deprotonation of the cellulose carboxyl groups. The experimental maximum adsorption capacity was 196 mg/g. This study highlights the potential of cellulose nanomaterial adsorbents and the importance of controlling the charge of the adsorbent material when developing solutions for ionizable micropollutant removal

Novel, smart and RFID assisted critical temperature indicator for supply chain monitoring

Abstract In order to reduce food waste and meet the needs of the demanding modern consumer regarding the quality of food items, it is crucial to monitor the supply chain and storage conditions of perishable food products. Considering this scenario, temperature plays an important role on food safety and quality during storage and supply. In this work, a critical temperature indicator (CTI) based on a solvent melting point is developed. Furthermore, the present CTI working principle is improved by the use of microfluidics technology. As final result, a novel and functional CTI-smart sensor which combines irreversible visual color changes and radio frequency identification (RFID) technologies is achieved. Such CTI integrated to a RFID tag provides a unique advantage to monitor the supply chain in real time by the simple use of a RFID reader in strategic points

CBS reductions with a fluorous prolinol immobilized in a hydrofluoroether solvent

A fluorous prolinol precatalyst bearing only 34 fluorine atoms has been immobilized in the hydrofluoroether solvent HFE-7500. The CBS reduction of acetophenone proceeded rapidly, in high yield and in high ee in the absence of any organic solvent. The organic product was stripped from the HFE-7500 phase with a polar solvent, and the HFE-7500 phase was reused "as is" with satisfactory results through eight runs. This process is an attractive prototype for the large-scale use, recovery, and reuse of fluorous organocatalysts. © 2008 American Chemical Society