Performance evaluation of phosphonium based deep eutectic solvents coated cerium oxide nanoparticles for CO2 capture.

The critical challenge being faced by our current modern society on a global scale is to reduce the surging effects of climate change and global warming, being caused by anthropogenic emissions of CO2 in the environment. Present study reports the surface driven adsorption potential of deep eutectic solvents (DESs) surface functionalized cerium oxide nanoparticles (CeNPs) for low pressure CO2 separation. The phosphonium based DESs were prepared using tetra butyl phosphoniumbromide as hydrogen bond acceptor (HBA) and 6 acids as hydrogen bond donors (HBDs). The as-developed DESs were characterized and employed for the surface functionalization of CeNPs with their subsequent utilization in adsorption-based CO2 adsorption. The synthesis of as-prepared DESs was confirmed through FTIR measurements and absence of precipitates, revealed through visual observations. It was found that DES6 surface functionalized CeNPs demonstrated 27% higher adsorption performance for CO2 capturing. On the contrary, DES3 coated CeNPs exhibited the least adsorption progress for CO2 separation. The higher adsorption performance associated with DES6 coated CeNPs was due to enhanced surface affinity with CO2 molecules that must have facilitated the mass transport characteristics and resulted an enhancement in CO2 adsorption performance. Carboxylic groups could have generated an electric field inside the pores to attract more polarizable adsorbates including CO2, are responsible for the relatively high values of CO2 adsorption. The quadruple movement of the CO2 molecules with the electron-deficient and pluralizable nature led to the enhancement of the interactive forces between the CO2 molecules and the CeNPs decorated with the carboxylic group hydrogen bond donor rich DES. The current findings may disclose the new research horizons and theoretical guidance for reduction in the environmental effects associated with uncontrolled CO2 emission via employing DES surface coated potential CeNPs.

Knowledge, attitude, and behaviour of dentists working during the COVID-19 pandemic: A cross-sectional survey.

BACKGROUND: The coronavirus disease 2019 (COVID-19) has immensely affected the world's population at physical and psychosocial levels. Dentists are no different from other healthcare providers, as they are equally if not more exposed to the threat of getting infected. OBJECTIVE: To assess the experience and behavior of public and private sector dentists practicing during the COVID-19 pandemic and their knowledge about it. METHODS: A cross-sectional survey was conducted online by sharing google forms through email, WhatsApp, and Facebook. The survey included questions on the knowledge, attitude, and behavior of dentists practicing during COVID-19. The data was interpreted by SPSS 24 using a chi-square test, and a value of p < 0.05 was considered significant. RESULTS: A considerable number of general dentists (26.9%) and specialists (39.4%) adopted partial suspension of clinics. Restriction's ease allowed 50.2% of the clinicians to resume their duties. 67.9% of the patients were medicated online during the lockdown phase. There was no significant difference regarding years of experience and willingness to treat/care (p-value 0.648). Personal protective equipment (PPE) was readily available for use in public or private practices, and the respondents agreed with its efficacy in protecting the operators. Compliance with PPE wear was 50% in all the respondents. CONCLUSION: The psychosocial repercussion of the pandemic continues to affect dental practices. Our attitude needs to improve as far as PPE is concerned, with regular training workshops and continuous updates of the developing Knowledge on COVID-19.

Template-based textural modifications of polymeric graphitic carbon nitrides towards waste water treatment.

The composite materials based on graphitic carbon nitrides (g-C3N4) are remarkably better semiconductors, but the inherent photocatalytic performance in its generic synthesis form is not up to the mark. Eminence efforts have been made to improve its performance and photocatalytic efficiencies. Recently, extensive investigations have been performed to develop their texturally modified and highly porous structures to get around the big flaws of bulk g-C3N4. One significant disadvantage is the increase in the polycondensation while preparation at 550 °C results in g-C3N4 materials with restricted specific surface area (SSA) (<10 m2/g) and no textured pores. Textural modification has emerged as an efficient and progressive way to improve optical and electronic characteristics. The final texture and shape of CN are influenced by the precursor's interaction with the template. Researchers are interested in developing CN materials with high SSA and changeable textural properties (pore volume and pore size). Based on the literature review it is concluded that the soft templating approach is relatively simple, and straightforward to induce textural changes in the g-CN type materials. This review focused on improving the textural properties of bulk g-C3N4 via templating method, and the major advances in the modified g-C3N4 materials for the treatment of wastewater. The procedures and mechanisms of numerous approaches with varying morphologies are thoroughly explained.

Cyclic oxygen exchange capacity of Ce-doped V2O5 materials for syngas production via high-temperature thermochemical-looping reforming of methane.

Synthesis gas production via solar thermochemical reduction-oxidation reactions is a promising pathway towards sustainable carbon-neutral fuels. The redox capability of oxygen carriers with considerable thermal and chemical stability is highly desirable. In this study, we report Ce-doped V2O5 structures for high-temperature thermochemical-looping reforming of methane coupled to H2O and CO2 splitting reactions. Incorporation of fractional amounts of large cerium cations induces a V5+ to V3+ transition and partially forms a segregated CeVO4 phase. More importantly, the effective combination of efficient ion mobility of cerium and high oxygen exchange capacity of vanadia achieves synergic and cyclable redox performance during the thermochemical reactions, whereas the pure vanadia powders undergo melting and show non-cyclic redox behaviour. These materials achieve noteworthy syngas production rates of up to 500 mmol molV -1 min-1 during the long-term stability test of 100 CO2 splitting cycles. Interestingly, the cerium ions are mobile between the lattice and the surface of the Ce-doped vanadia powders during the repeated reduction and oxidation reactions and contribute towards the cyclic syngas production. However, this also causes the formation of the CeVO4 phase in Ce-rich powders, which increases the H2/CO ratios and lowers fuel selectivity, which can be controlled by optimizing the cerium concentration. These findings are noteworthy towards the experimental approach of evaluating the oxygen carriers with the help of advanced characterization techniques.

What Makes People Hide Knowledge? Influence of Passive Leadership and Creative Self-Efficacy.

Although numerous studies have been conducted in the field of knowledge sharing with a focus given to its importance, very little attention has been given to knowledge hiding practices. A very few studies have been found to make an attempt to figure out its impact and antecedents. Likewise, the negative role of passive leadership in the project management literature has not been evidenced enough despite its existence in project-based organizations. Both knowledge hiding and passive leadership are the highly neglected areas in the project management literature. Therefore, this study not only attempts to investigate the influence of passive leadership on knowledge hiding but also aims to explore the role of creative self-efficacy between them. IT project organizations were chosen to collect data because of their high failure rate due to an insufficient knowledge transfer. The findings of this study revealed that the neglected passive leadership greatly influences the knowledge hiding practices among individuals. However, according to the results, knowledge hiding practices are found to reduce the presence of creative self-efficacy. Thus, the antecedents of knowledge hiding should be considered to create an innovative and successful business environment. The results are highly significant not only for the field of project management but also for other practitioners.

Development and Comparative Analysis of Electrochemically Etched Tungsten Tips for Quartz Tuning Fork Sensor.

Quartz Tuning Fork (QTF) based sensors are used for Scanning Probe Microscopes (SPM), in particular for near-field scanning optical microscopy. Highly sharp Tungsten (W) tips with larger cone angles and less tip diameter are critical for SPM instead of platinum and iridium (Pt/Ir) tips due to their high-quality factor, conductivity, mechanical stability, durability and production at low cost. Tungsten is chosen for its ease of electrochemical etching, yielding high-aspect ratio, sharp tips with tens of nanometer end diameters, while using simple etching circuits and basic electrolyte chemistry. Moreover, the resolution of the SPM images is observed to be associated with the cone angle of the SPM tip, therefore Atomic-Resolution Imaging is obtained with greater cone angles. Here, the goal is to chemically etch W to the smallest possible tip apex diameters. Tips with greater cone angles are produced by the custom etching procedures, which have proved superior in producing high quality tips. Though various methods are developed for the electrochemical etching of W wire, with a range of applications from scanning tunneling microscopy (SPM) to electron sources of scanning electron microscopes, but the basic chemical etching methods need to be optimized for reproducibility, controlling cone angle and tip sharpness that causes problems for the end users. In this research work, comprehensive experiments are carried out for the production of tips from 0.4 mm tungsten wire by three different electrochemical etching techniques, that is, Alternating Current (AC) etching, Meniscus etching and Direct Current (DC) etching. Consequently, sharp and high cone angle tips are obtained with required properties where the results of the W etching are analyzed, with optical microscope, and then with field emission scanning electron microscopy (FE-SEM). Similarly, effects of varying applied voltages and concentration of NaOH solution with comparison among the produced tips are investigated by measuring their cone angle and tip diameter. Moreover, oxidation and impurities, that is, removal of contamination and etching parameters are also studied in this research work. A method has been tested to minimize the oxidation on the surface and the tips were characterized with scanning electron microscope (SEM).

Concentration-Dependent Solar Thermochemical CO2/H2O Splitting Performance by Vanadia-Ceria Multiphase Metal Oxide Systems.

The effects of V and Ce concentrations (each varying in the 0-100% range) in vanadia-ceria multiphase systems are investigated for synthesis gas production via thermochemical redox cycles of CO2 and H2O splitting coupled to methane partial oxidation reactions. The oxidation of prepared oxygen carriers is performed by separate and sequential CO2 and H2O splitting reactions. Structural and chemical analyses of the mixed-metal oxides revealed important information about the Ce and V interactions affecting their crystal phases and redox characteristics. Pure CeO2 and pure V2O5 are found to offer the lowest and highest oxygen exchange capacities and syngas production performance, respectively. The mixed-oxide systems provide a balanced performance: their oxygen exchange capacity is up to 5 times higher than that of pure CeO2 while decreasing the extent of methane cracking. The addition of 25% V to CeO2 results in an optimum mixture of CeO2 and CeVO4 for enhanced CO2 and H2O splitting. At higher V concentrations, cyclic carbide formation and oxidation result in a syngas yield higher than that for pure CeO2.

Fractionation of Lignocellulosic Biomass over Core-Shell Ni@Al2 O3 Catalysts with Formic Acid as a Cocatalyst and Hydrogen Source.

Highly dispersed, core-shell Ni@Al2 O3 on activated carbon (AC) catalysts were prepared to develop an effective, external-hydrogen-free fractionation process for various types of lignocellulosic biomass. In a mixture of formic acid, ethanol, and water at 190 °C, the conversion of oak wood produced 23.4 C% lignin-derived phenolic monomers (LDPMs) and highly delignified pulp-rich solid. At an early stage, formic acid acted as a cocatalyst to enhance the delignification by solvolysis, and at a later stage, it acted as a hydrogen source to stabilize the phenolic monomers by hydrodeoxygenation and hydrogenation. Based on the positive correlation between spillover hydrogen on the catalysts and LDPM yields, a new suite of catalyst design criteria was proposed to develop highly active, non-noble-metal based catalysts for realizing economically viable biorefineries. Enzymatic saccharification of the pulp-rich solid indicated that the pulp-rich solid is an excellent source of fermentable sugars.

Enhanced mechanical, thermal and antimicrobial properties of poly(vinyl alcohol)/graphene oxide/starch/silver nanocomposites films.

In the present work, synthesis of poly(vinyl alcohol)/graphene oxide/starch/silver (PVA/GO/Starch/Ag) nanocomposites films is reported. Such films have been characterized and investigated for their mechanical, thermal and antimicrobial properties. The exfoliation of GO in the PVA matrix occurs owing to the non-covalent interactions of the polymer chains of PVA and hydrophilic surface of the GO layers. Presence of GO in PVA and PVA/starch blends were found to enhance the tensile strength of the nanocomposites system. It was found that the thermal stability of PVA as well as PVA/starch blend systems increased by the incorporation of GO where strong physical bonding between GO layers and PVA/starch blends is assumed to cause thermal barrier effects. Antimicrobial properties of the prepared films were investigated against Escherichia coli and Staphylococcus aureus. Our results show enhanced antimicrobial properties of the prepared films where PVA-GO, PVA-Ag, PVA-GO-Ag and PVA-GO-Ag-Starch showed antimicrobial activity in ascending order.

Liquid crystals based sensing platform-technological aspects.

In bulk phase, liquid crystalline molecules are organized due to non-covalent interactions and due to delicate nature of the present forces; this organization can easily be disrupted by any small external stimuli. This delicate nature of force balance in liquid crystals organization forms the basis of Liquid-crystals based sensing scheme which has been exploited by many researchers for the optical visualization and sensing of many biological interactions as well as detection of number of analytes. In this review, we present not only an overview of the state of the art in liquid crystals based sensing scheme but also highlight its limitations. The approaches described below revolve around possibilities and limitations of key components of such sensing platform including bottom substrates, alignments layers, nature and type of liquid crystals, sensing compartments, various interfaces etc. This review also highlights potential materials to not only improve performance of the sensing scheme but also to bridge the gap between science and technology of liquid crystals based sensing scheme.

From Eye Drops to ICU, a Case Report of Three Side Effects of Ophthalmic Timolol Maleate in the Same Patient.

Timolol Maleate (also called Timolol) is a nonselective beta-adrenergic blocker and a class II antiarrhythmic drug, which is used to treat intraocular hypertension. It has been reported to cause systemic side effects especially in elderly patients with other comorbidities. These side effects are due to systemic absorption of the drug and it is known that Timolol is measurable in the serum following ophthalmic use. Chances of life threatening side effects increase if these are coprescribed with other cardiodepressant drugs like calcium channel or systemic beta blockers. We report a case where an elderly patient was admitted with three side effects of Timolol and his condition required ICU admission with mechanical ventilation and temporary transvenous pacing. The case emphasizes the need of raising awareness among physicians of such medications about the potential side effects and drug interactions. A close liaison among patient's physicians is suggested.