Solution stoichiometry determines crystal stoichiometry in halogen-bonded supramolecular complexes (original) (raw)
Polymers
Segmented poly(urethane-imide)s (PUIs) were synthesized by polyaddition reaction and applied for preparation of membranes. Tolylene-2,4-diisocyanate, pyromellitic dianhydride, and m-phenylenediamine for chain extension were used to form hard aromatic blocks. Polycaprolactone diols with molecular weights equal to 530 and 2000 g mol−1 were chosen as soft segments. The effect of the length of soft segments on the structure, morphology, and transport properties of segmented poly(urethane-imide) membranes were studied using atomic force microscopy, small-angle and wide-angle X-ray scattering, and pervaporation experiments. It was found that a copolymer with a shorter soft segment (530 g mol−1) consists of soft domains in a hard matrix, while the introduction of polycaprolactone blocks with higher molecular weight (2000 g mol−1) leads to the formation of hard domains in a soft matrix. Additionally, the introduction of hard segments prevents crystallization of polycaprolactone. Transport p...
Aminoazole-Based Diversity-Oriented Synthesis of Heterocycles
Frontiers in Chemistry
The comprehensive review contains the analysis of literature data concerning reactions of heterocyclization of aminoazoles and demonstrates the application of these types of transformations in diversity-oriented synthesis. The review is oriented to wide range of chemists working in the field of organic synthesis and both experimental and theoretical studies of nitrogen-containing heterocycles.
Frontiers in microbiology, 2017
Plasmonic nanoparticles (NPs) such as silver and gold have fascinating optical properties due to their enhanced optical sensitivity at a wavelength corresponding to their surface plasmon resonance (SPR) absorption. Present work deals with the fabrication of silver nanoparticles decorated cotton (SNDC) fibers as a cheap and efficient point of contact disinfectant. SNDC fibers were fabricated by a simple microwave assisted route. The microwave power and irradiation time were controlled to optimize size and density of silver nanoparticles (SNPs) on textile fibers. As prepared cotton fabric was characterized for ATR-FTIR, UV-VIS diffuse reflectance, SEM and TEM investigations. Size of SNPs as well as total density of silver atoms on fabric gets increased with the increase of microwave power from 100 W to 600 W. The antibacterial efficacy of SNPs extracted from SNDC fibers was found to be more effective against Gram-negative bacteria than Gram-positive bacteria with MIC 38.5 ± 0.93 μg/mL...
Nanoscale Research Letters
Various concentrations of Mg-doped ZnO nanorods (NRs) were prepared using co-precipitation technique. The objective of this study was to improve the photocatalytic properties of ZnO. The effect of Mg doping on the structure, phase constitution, functional groups presence, optical properties, elemental composition, surface morphology and microstructure of ZnO was evaluated with XRD, FTIR, UV–Vis spectrophotometer, EDS, and HR-TEM, respectively. Optical absorption spectra obtained from the prepared samples showed evidence of blueshift upon doping. XRD results revealed hexagonal wurtzite phase of nanocomposite with a gradual decrease in crystallite size with Mg addition. PL spectroscopy showed trapping efficiency and migration of charge carriers with electron–hole recombination behavior, while HR-TEM estimated interlayer d-spacing. The presence of chemical bonding, vibration modes and functional groups at the interface of ZnO was revealed by FTIR and Raman spectra. In this study, photo...
Molecules
The synthesis of polymer-grafted nanoparticles (PGNPs) or hairy nanoparticles (HNPs) by tethering of polymer chains to the surface of nanoparticles is an important technique to obtain nanostructured hybrid materials that have been widely used in the formulation of advanced polymer nanocomposites. Ceramic-based polymer nanocomposites integrate key attributes of polymer and ceramic nanomaterial to improve the dielectric properties such as breakdown strength, energy density and dielectric loss. This review describes the “grafting from” and “grafting to” approaches commonly adopted to graft polymer chains on NPs pertaining to nano-dielectrics. The article also covers various surface initiated controlled radical polymerization techniques, along with templated approaches for grafting of polymer chains onto SiO2, TiO2, BaTiO3, and Al2O3 nanomaterials. As a look towards applications, an outlook on high-performance polymer nanocomposite capacitors for the design of high energy density pulsed...
Food Analytical Methods, 2017
Foodborne ailments constitute a public health challenge and pose an incredible economic burden in healthcare system around the globe. This dilemma has urged authorities and other entities working in field of food quality control and supply chain to play a pivotal role in ensuring food safety. Analytical strategies have been developed using numerous systematic evolution of ligands by exponential enrichment (SELEX) methods to assure food safety. High-affinity and high-sensitivity ssDNA and RNA aptamers against pathogens have emerged as a novel strategy, as compared to the more resource-demanding and complicated biochemical test-based approaches. Thus, this review aims to focus on some methods used in the selection of specific bare, modified, and conjugated aptamers and on the further analysis of selected aptamers using flow cytometer or post-SELEX modifications for enhanced detection of frequently diagnosed foodborne bacteria such as Bacillus sp., Campylobacter jejuni, Escherichia sp., Salmonella sp., Staphylococcus aureus, Shigella sp., Listeria monocytogenes, and Streptococcus pyogenes and/or targeting their cell components towards attaining fast, sensitive, and selective methods for the detection of pathogens in food(s) or other sources.
Scientific reports, 2017
Recent discovery of the pyrite FeO2, which can be an important ingredient of the Earth's lower mantle and which in particular may serve as an extra source of water in the Earth's interior, opens new perspectives for geophysics and geochemistry, but this is also an extremely interesting material from physical point of view. We found that in contrast to naive expectations Fe is nearly 3+ in this material, which strongly affects its magnetic properties and makes it qualitatively different from well known sulfide analogue - FeS2. Doping, which is most likely to occur in the Earth's mantle, makes FeO2 much more magnetic. In addition we show that unique electronic structure places FeO2 "in between" the usual dioxides and peroxides making this system interesting both for physics and solid state chemistry.
Bismuth-Based Compounds as Visible Light Photocatalyst for Remediation and Water Splitting
2020
Enhancing demand for environmental protection has become an urgent need more than ever. For this purpose, water the most known indispensable essences for survivorship of aboveground organisms should be specifically considered. Today, quality of water as dominant source influence of the animate systems has been endangered by various harmful contamination levels. Accordingly, rescuing approaches and cleaning compounds in safe manner demanding for improvement of the quality of potable and industrial utilizing waters are daily pursued. Different materials of bismuth having layered structures, hybridized orbitals, low band gap, and band positions can be attended because of significant ability of water remediation. At this book chapter, we reviewed the photocatalytic efficiency of BiÀcompounds, the heterojunction and ZÀscheme composites of them, and the synthetization method. Heterojunction or ZÀscheme combinations led to obtain high separation photogenerated electronsÀhole and reduction of the recombination rate. Furthermore, type II of heterojunction and ZÀscheme connections with other
Sensors (Basel, Switzerland), 2017
Current research on Unmanned Aerial Vehicles (UAVs) shows a lot of interest in autonomous UAV navigation. This interest is mainly driven by the necessity to meet the rules and restrictions for small UAV flights that are issued by various international and national legal organizations. In order to lower these restrictions, new levels of automation and flight safety must be reached. In this paper, a new method for ground obstacle avoidance derived by using UAV navigation based on the Dubins paths algorithm is presented. The accuracy of the proposed method has been tested, and research results have been obtained by using Software-in-the-Loop (SITL) simulation and real UAV flights, with the measurements done with a low cost Global Navigation Satellite System (GNSS) sensor. All tests were carried out in a three-dimensional space, but the height accuracy was not assessed. The GNSS navigation data for the ground obstacle avoidance algorithm is evaluated statistically.
2021
The development of society is dependent on commodities such as fuels and chemical feedstock. Most of these commodities are obtained from oil as raw material. Although the need to find a friendly solution to couple an economically viable energy model with a greener solution, it is known that technologies applying renewable sources are in an early stage of development. The conversion of methane into clean fuels or chemical feedstock with high commercial value, such as hydrogen, ethylene, or methanol is interesting from the energetic and economic point-of-view. Among the methods of methane conversion, the industrially used is the steam reforming (MSR), in which methane reacts with water to produce syngas, a mixture of CO and H2. Nevertheless, this reaction is highly endothermic and responsible for a large volume of CO2 emitted by the reactor burners that provide energy to the reactors. An interesting alternative process for methane conversion is the dry reforming of methane (DRM), whic...
Sunlight-driven photocatalytic degradation of Rhodamine B by BiOCl and TiO2 deposited on NiCr-LDH
2021
This research aims at analysing the pragmatic prominent discourse in the public sphere, the digital sphere in particular, that reflects special changes in the society. The meant discourse has not been investigated adequately and sufficiently namely the social, the political and the digital virtual discourses which bear an effective semantic and pragmatic power on the public space and at the same time incorporate strong transformations in the values patterns. This study utilizes a pragmatic approach, since the pragmatics is a study of using language in communication, and works on analysing daily discourses using a journalistic editorial. So, what are the changes reflected by this discourse? And what are the values represented and expressed by the prevailing discourses in the public sphere?
The Synergistic Properties and Gas Sensing Performance of Functionalized Graphene-Based Sensors
Materials, 2022
The detection of toxic gases has long been a priority in industrial manufacturing, environmental monitoring, medical diagnosis, and national defense. The importance of gas sensing is not only of high benefit to such industries but also to the daily lives of people. Graphene-based gas sensors have elicited a lot of interest recently, due to the excellent physical properties of graphene and its derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO). Graphene oxide and rGO have been shown to offer large surface areas that extend their active sites for adsorbing gas molecules, thereby improving the sensitivity of the sensor. There are several literature reports on the promising functionalization of GO and rGO surfaces with metal oxide, for enhanced performance with regard to selectivity and sensitivity in gas sensing. These synthetic and functionalization methods provide the ideal combination/s required for enhanced gas sensors. In this review, the functionalization o...
Graphene Oxide-Doped MgO Nanostructures for Highly Efficient Dye Degradation and Bactericidal Action
Nanoscale Research Letters, 2021
Various concentrations (0.01, 0.03 and 0.05 wt ratios) of graphene oxide (GO) nanosheets were doped into magnesium oxide (MgO) nanostructures using chemical precipitation technique. The objective was to study the effect of GO dopant concentrations on the catalytic and antibacterial behavior of fixed amount of MgO. XRD technique revealed cubic phase of MgO, while its crystalline nature was confirmed through SAED profiles. Functional groups presence and Mg-O (443 cm−1) in fingerprint region was evident with FTIR spectroscopy. Optical properties were recorded via UV–visible spectroscopy with redshift pointing to a decrease in band gap energy from 5.0 to 4.8 eV upon doping. Electron–hole recombination behavior was examined through photoluminescence (PL) spectroscopy. Raman spectra exhibited D band (1338 cm−1) and G band (1598 cm−1) evident to GO doping. Formation of nanostructure with cubic and hexagon morphology was confirmed with TEM, whereas interlayer average d-spacing of 0.23 nm wa...
Polymers, 2020
In the present study, a chitosan (CS) derivative with the 2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SDAEM) zwitterionic monomer was prepared through chemical modification. The successful synthesis of CS-SDAEM was confirmed by Fourier-transform Infrared (FTIR) and Nuclear Magnetic Resonance (1H-NMR) spectroscopies. Its crystallinity was studied by X-ray Diffraction (XRD), while in vitro cytotoxicity and cell viability assays established its biocompatibility. Filtered fresh pomegranate juice (PJ) was loaded in nanoparticles of neat CS and its derivative via ionic gelation method. Dynamic Light Scattering (DLS) revealed nanoparticles sizes varying between 426 nm and 4.5 μm, indicating a size-dependence on the polymer concentration used during encapsulation. High-performance liquid chromatography coupled with photodiode array and electrospray ionization mass spectrometry detection (LC-PDA-ESI/MS) revealed that PJ active compounds were successfully and in suffi...
Vibrational spectroscopy and chemometrics in GSR: review and current trend
Egyptian Journal of Forensic Sciences, 2021
Background This review represents many significant methods of chemometrics applied as data assessment methods originated by many hyphenated analytical techniques containing their application since its origin to today. Main body of the abstract The study has been divided into many parts, which contain many multivariate regression methods. The main aim of this study is to investigate the chemometrics tools used in GSR (gunshot residue) or forensic ballistics. Short conclusion As a final point, the end of part of this review deals with the applicability of chemometric methods in forensic ballistics. We select to give an elaborate description of many significant tools established with their algorithm in admire of utilizing and accepting them by researchers not very aware with chemometrics.
Polymers, 2018
Poly(ε-caprolactone) (PCL) is a bioresorbable synthetic polyester widely studied as a biomaterial for tissue engineering and controlled release applications, but its low bioactivity and weak mechanical performance limits its applications. In this work, nanosized bioglasses with two different compositions (SiO 2-CaO and SiO 2-CaO-P 2 O 5) were synthesized with a hydrothermal method, and each one was used as filler in the preparation of PCL nanocomposites via the in situ ring opening polymerization of ε-caprolactone. The effect of the addition of 0.5, 1 and 2.5 wt % of the nanofillers on the molecular weight, structural, mechanical and thermal properties of the polymer nanocomposites, as well as on their enzymatic hydrolysis rate, bioactivity and biocompatibility was systematically investigated. All nanocomposites exhibited higher molecular weight values in comparison with neat PCL, and mechanical properties were enhanced for the 0.5 and 1 wt % filler content, which was attributed to extensive interactions between the filler and the matrix, proving the superiority of in situ polymerization over solution mixing and melt compounding. Both bioglasses accelerated the enzymatic degradation of PCL and induced bioactivity, since apatite was formed on the surface of the nanocomposites after soaking in simulated body fluid. Finally, all samples were biocompatible as Wharton jelly-derived mesenchymal stem cells (WJ-MSCs) attached and proliferated on their surfaces.
Journal of Materials Science, 2018
Sulfonated ABA triblock copolymers were synthesized based on ionomers with a hydrophilic block such as sulfonated poly(ether ether sulfone) (sPEES) and hydrophobic blocks such as poly(methyl methacrylate) (PMMA) and poly(pentafluorostyrene) (PPFS). The formation of these copolymers was evidenced by Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1 H NMR), and gel permeation chromatography (GPC) analyses. The copolymers were used to prepare membranes by two approaches: direct selfassembly and infiltration of the polymers into anodized aluminum oxide (AAO) templates. The effect of the copolymer chemical structure (fluorinated and nonfluorinated) and preparation method on the properties of the membranes, such as morphology, thermal stability, water uptake, ion exchange capacity (IEC), and proton conductivity, was evaluated. Both methods used to obtain membranes from ABA copolymers synthesized were successful. Morphological characterization showed that the fluorinated membranes prepared by selfassembly exhibited phase separation. This phase-segregated morphology of partially fluorinated block copolymer structures and high density of sulfonic acid groups had a positive impact on proton exchange capacity and proton conductivity. Moreover, methanol permeability was improved in comparison with Nafion Ò 117. Otherwise, the morphology of AAO membranes pores filled by infiltration was verified, and the proton conductivity was low due to an increase in the tortuosity which affected proton transport. The present study shows that the membranes prepared by self-assembly of sulfonated ABA block copolymers presented the best properties to be applied as proton exchange membranes.
Review on carbon-based electrode materials for application in capacitive deionization process
International Journal of Environmental Science and Technology, 2016
Most of the electrochemical studies related to porous carbon electrodes are those which can be used for either electrostatic energy storage or for energy conversion [using electrical double layer capacitor (EDLC)]. The techniques, such as electrodialysis, membrane filtration, advanced oxidation process, thermal evaporation, can be used now-a-days to treat salty water. Among which, capacitive deionization (CDI) has emerged as a novel cost effective and environment friendly desalination technology. CDI process involves the removal of inorganic ions from the salty water by applying an electrical potential between two porous carbon electrodes. Because of the passage of electrical potentials in the system, the unwanted ions present in the water sample will be adsorbed on the electrode surfaces. Hence, the electrodes which are having high surface area can exhibit higher desalination capacity. In this article, the application of various carbon-based composite electrode materials such as activated carbon and PVDF composite, carbon-metal oxide composite, carbon-CNT composite, carbon-polymer composite and carbon sheet (carbon aerogel, activated carbon cloth) in CDI process is systematically reviewed and presented. CDI process is being developed now-a-days especially toward commercialization in treating the brackish water.
Applied Water Science, 2020
In this study, the scales of Micropogonias undulatus fish were investigated as precursors for the development of low-cost biosorbent for the removal of Pb(II) and Zn(II) from aqueous media. The biosorbent was characterised using Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-ray diffractometry (XRD). Adsorption parameters (temperature, biosorbent dosage and contact time) were optimised using response surface methodology Box–Behnken experimental design. The optimal factors for Zn(II) removal by croaker fish scale were 145.5 min, 7.01 g/L biosorbent dosage, 30 °C and pH 5.4. The optimal factors for the removal of Pb(II) were 179.3 min, 6.61 g/L biosorbent dosage, 20 °C and pH 3.4. The numerical optimisation revealed that the optimal removal efficiency for Zn(II) and Pb(II) sorption is 96.45% and 98.76%, respectively. The biosorption of both heavy metals was best fit to Freundlich isotherm and pseudo-second-order kinetic models. Thermodynamics ...
International Journal of Nanomedicine
In the search for new drug delivery platforms for cardiovascular diseases and coating of medical devices, we synthesized eptifibatide-functionalized silver nanoparticles (AgNPs-EPI) and examined the pharmacological activity of AgNPs-EPI on platelets and endothelial cells in vitro and ex vivo. Methods: Spherical AgNPs linked to eptifibatide were synthesized and characterized. Cytotoxicity was measured in microvascular endothelial cells (HMEC-1), platelets and red blood cells. Platelet mitochondrial respiration was measured using the Oxygraph-2k, a high-resolution modular respirometry system. The effect of AgNPs-EPI on the aggregation of washed platelets was measured by light aggregometry and the ex vivo occlusion time was determined using a reference laboratory method. The surface amount of platelet receptors such as P-selectin and GPIIb/IIIa was measured. The influence of AgNPS-EPI on blood coagulation science was assessed. Finally, the effect of AgNPs-EPI on endothelial cells was measured by the levels of 6-keto-PGF1alpha, tPa, cGMP and vWF. Results: We describe the synthesis of AgNPs using eptifibatide as the stabilizing ligand. The molecules of this drug are directly bonded to the surface of the nanoparticles. The synthesized AgNPs-EPI did not affect the viability of platelets, endothelial cells and erythrocytes. Preincubation of platelets with AgNPs-EPI protected by mitochondrial oxidative phosphorylation capacity. AgNPs-EPI inhibited aggregation-induced P-selectin expression and GPIIb/IIIa conformational changes in platelets. AgNPs-EPI caused prolongation of the occlusion time in the presence of collagen/ADP and collagen/adrenaline. AgNPs-EPI regulated levels of 6-keto-PGF1alpha, tPa, vWf and cGMP produced in thrombin stimulated HMEC-1 cells. Conclusion: AgNPs-EPI show anti-aggregatory activity at concentrations lower than those required by the free drug acting via regulation of platelet aggregation, blood coagulation, and endothelial cell activity. Our results provide proof-of-principle evidence that AgNPs may be used as an effective delivery platform for antiplatelet drugs.
Scientific Reports, 2021
Magnesium-based implants (MBIs) have recently attracted great attention in bone regeneration due to elastic modulus similar to bone. Nevertheless, the degradation rate and hydrogen release of MBIs in the body have to be tackled for practical applications. In the present study, we present a metal–organic framework (MOF) nanoplates to reduce the degradation rate of AZ91 magnesium alloy. Zeolitic imidazolate frameworks (ZIF-8) with a specific surface area of 1789 m2 g−1 were prepared by solvothermal methods, and after dispersion in a chitosan solution (10% w/w), the suspension was electrospun on the surface of AZ91 alloy. Studying the degradation rate in simulated body fluid (SBF) by electrochemical analysis including potentiodynamic polarization and electrochemical impedance spectroscopy reveals that the degradation rate of the surface-modified implants decreases by ~ 80% as compared with the unmodified specimens. The reduced alkalization of the physiological environment and hydrogen ...
Synthesis and characterization of calcium oxide nanoparticles for CO2 capture
Journal of Nanoparticle Research
In this paper, the preparation of calcium oxide (CaO) nanoparticles (NPs) is reported by a precipitation method, using CaCl2 and NaOH as starting raw materials. The produced NPs were characterized for chemical composition, phase composition, particle size distribution, morphological features, specific surface area, and crystallite sizes. It is shown that calcination of Ca(OH)2 in vacuum takes place faster/at a lower temperature compared to the calcination in air due to the higher entropy of the gaseous product of calcination. It is also shown that when these CaO nanoparticles are kept at room temperature in air, they fully and spontaneously transform into CaCO3 within 3 weeks. Therefore, if this material is disposed in open fields (not necessarily in industrial conditions), it is able to capture carbon dioxide from normal air slowly, but surely. However, when the CaO nanoparticles are kept in the air at 100–200 °C, they mostly capture water vapor from the air instead of carbon dioxi...
Power Quality Improvement for Vehicle-to-Grid and Grid-to-Vehicle Technology in a Microgrid
International Transactions on Electrical Energy Systems
The demand for electric vehicles continues to grow, as evidenced by global sales of electric vehicles reaching 2.2 million in 2019 and more than doubling to 6.6 million in 2021. The rapid growth of renewable energies and electric vehicles (EVs) necessitates the use of microgrids, which are a promising solution to the problem of integrating large-scale renewables and EVs into the electric power system. Besides, the essential policy support provided by the government is an increase in the availability of public charging infrastructure for EVs. This research employs a fast-charging configuration of an off-board charger with DC energy transfer. Implementation of DC energy transfer for vehicle-to-grid and grid-to-vehicle technology in a microgrid due to DC charging’s unrestricted charger-rated power and rapid power transfer. However, the integration of EVs in the Microgrid system creates some operational challenges, which in this research are power quality issues such as harmonics in pow...
Chemistry Africa
supportive nanomaterial anti COVID-19, as TiO 2 material [8]. As seen in Fig. 1, nanoparticles are generally produced via green, physical, and chemical methods [9]. The commonly applied physical processes to produce nanoparticles are thermal decomposition, sputtering, and sonication [10]. However, chemical reduction, sol-gel, and colloidal chemical methods are some of the most commonly used chemical synthesis methods. In contrast, the sol-gel process is one of the most frequently used techniques for developing nanoparticles since it produces highly pure nanoparticles at an appropriate pH at lower temperatures [11]. As well, the kinetics of their reactions can be controlled. However, a wide variety of biological entities are exploited in the synthesis of NPs, such as plants, algae, fungi, yeast, bacteria, and viruses. Tetraethyl orthosilicate (TEOS) and tetramethyl orthosilicate (TMOS) are commonly employed as precursors to synthesize SiO 2 nanoparticles using chemical methods. However, the high pricing and toxicities of TEOS and TMOS precursors make this process neither economical nor environmentally beneficial [12]. Therefore, it is beneficial to produce SiO 2 NPs from inexpensive, non-toxic, naturally occurring precursors using approaches that offer Recently, amorphous silica nanoparticles (SiO 2 NPs) have been receiving significant attention because of their exciting properties, including high porosity, biocompatibility, low toxicity, a specific surface area, ease of surface modification, and adjustable mechanical, chemical, optoelectronic, and physical characteristics [1, 2]. Therefore, SiO 2 nanoparticles were employed in numerous applications related to medicine, agriculture, drug delivery, cosmetics, water treatment systems, and energy devices [3-7]. Recent studies have demonstrated that SiO 2 NPs are a prospective Nassima Meftah
Co2TiO4/Reduced Graphene Oxide Nanohybrids for Electrochemical Sensing Applications
Nanomaterials, 2019
For the first time, the synthesis, characterization, and analytical application for hydrogen peroxide quantification of the hybrid materials of Co2TiO4 (CTO) and reduced graphene oxide (RGO) is reported, using in situ (CTO/RGO) and ex situ (CTO+RGO) preparations. This synthesis for obtaining nanostructured CTO is based on a one-step hydrothermal synthesis, with new precursors and low temperatures. The morphology, structure, and composition of the synthesized materials were examined using scanning electron microscopy, X-ray diffraction (XRD), neutron powder diffraction (NPD), and X-ray photoelectron spectroscopy (XPS). Rietveld refinements using neutron diffraction data were conducted to determine the cation distributions in CTO. Hybrid materials were also characterized by Brunauer–Emmett–Teller adsorption isotherms, Scanning Electron microscopy, and scanning electrochemical microscopy. From an analytical point of view, we evaluated the electrochemical reduction of hydrogen peroxide ...
International Journal of Polymeric Materials and Polymeric Biomaterials, 2019
Electrospinning fabricates nano dimensional fibers exhibiting characteristics such as tunable porosity, high surface to volume ratio and the ability to incorporate biocompatible materials in nano fibrous polymeric structures. The ease of fiber functionalization, economic viability and deposition of electro-spun fibers on variety of substrates has made electrospinning sought-after technique in the biomedical field. The applicability of bio-adaptable nanoscale electro-spun fibers is evident in tissue engineering, drug delivery, vascular grafts, implants and neural prostheses, bio-sensing and a plethora of other applications. This review summarizes types and parameters of electrospinning techniques essential for generating highly functional biocompatible nanofibers in future of biomedicine.
Recent advances in the biosorption of pollutants by fish scales: a mini-review
Chemical Engineering Communications, 2020
In the quest for environmental protection and sustainability, researchers have evaluated a variety of biomaterials for the remediation of polluted effluents. In this mini-review, the recent advances in biosorption of pollutants from aqueous solutions using fish scales was discussed. It was conducted to catalogue research progress, gain an understanding of the current research trend, isolate possible knowledge gaps, and elucidate potential future perspectives in the research area. Four (4) key stages are involved in the preparation methodology of biosorbents from fish scales: washing, drying, grinding, and sieving. Biosorbent from fish scales usually possess heterogeneous surfaces (and sometimes ridges). It was observed that about 65% of research studies have focused on heavy metals removal. Fish scale biosorption equilibrium was usually best fit to Langmuir or Freundlich isotherms and the biosorption kinetics was according to the pseudo-second-order model in most cases. Fish scale biosorption for metals was observed to be always spontaneous process. The current research trend in the area is on methods to improve the biosorbent via derivation of hydroxyapatite scaffolds, chemical impregnation, and other functionalization techniques.
Biomechanical Regulation of Hematopoietic Stem Cells in the Developing Embryo
Current Tissue Microenvironment Reports
Purpose of ReviewThe contribution of biomechanical forces to hematopoietic stem cell (HSC) development in the embryo is a relatively nascent area of research. Herein, we address the biomechanics of the endothelial-to-hematopoietic transition (EHT), impact of force on organelles, and signaling triggered by extrinsic forces within the aorta-gonad-mesonephros (AGM), the primary site of HSC emergence.Recent FindingsHemogenic endothelial cells undergo carefully orchestrated morphological adaptations during EHT. Moreover, expansion of the stem cell pool during embryogenesis requires HSC extravasation into the circulatory system and transit to the fetal liver, which is regulated by forces generated by blood flow. Findings from other cell types also suggest that forces external to the cell are sensed by the nucleus and mitochondria. Interactions between these organelles and the actin cytoskeleton dictate processes such as cell polarization, extrusion, division, survival, and differentiation...
Multiscale simulation of the focused electron beam induced deposition process
Scientific Reports, 2020
Focused electron beam induced deposition (FEBID) is a powerful technique for 3D-printing of complex nanodevices. However, for resolutions below 10 nm, it struggles to control size, morphology and composition of the structures, due to a lack of molecular-level understanding of the underlying irradiation-driven chemistry (IDC). Computational modeling is a tool to comprehend and further optimize FEBID-related technologies. Here we utilize a novel multiscale methodology which couples Monte Carlo simulations for radiation transport with irradiation-driven molecular dynamics for simulating IDC with atomistic resolution. Through an in depth analysis of \hbox {W(CO)}_6W(CO)6depositiononW(CO) 6 deposition onW(CO)6depositionon\hbox {SiO}_2$$ SiO 2 and its subsequent irradiation with electrons, we provide a comprehensive description of the FEBID process and its intrinsic operation. Our analysis reveals that simulations deliver unprecedented results in modeling the FEBID process, demonstrating an excellent agreement with ...
Role of Anions in the Synthesis and Crystal Growth of Selected Semiconductors
Frontiers in Chemistry
The ideal methods for the preparation of semiconductors should be reproducible and possess the ability to control the morphology of the particles with monodispersity yields. Apart from that, it is also crucial to synthesize a large quantity of desired materials with good control of size, shape, morphology, crystallinity, composition, and surface chemistry at a reasonably low production cost. Metal oxides and chalcogenides with various morphologies and crystal structures have been obtained using different anion metal precursors (and/or different sulfur sources for chalcogenides in particular) through typical synthesis methods. Generally, spherical particles are obtained as it is thermodynamically favorable. However, by changing the anion precursor salts, the morphology of a semiconductor is influenced. Therefore, precursors having different anions show some effects on the final forms of a semiconductor. This review compiled and discussed the effects of anions (NO3−, Cl−, SO42-, CH3CO...
Environmental Science and Pollution Research, 2023
In the present study, modi ed Fe 3 O 4 nanoparticles were fabricated by surface coating with tryptophan and Iridium by coprecipitation method to afford Fe 3 O 4 @trp@Ir magnetic nanoparticles. As-prepared Fe 3 O 4 @trp@Ir nanoparticles are environmentally benign e cient catalysts for reducing organic pollutants such as 4-nitrophenol (4-NP), 4-nitroaniline (4-NA), and 1-bromo-4-nitrobenzene (1-B-4-NB). The key parameters that affect the catalytic activity like temperature, catalyst loading, and the concentration of reducing agent NaBH 4 were optimized. The obtained results proved that Fe 3 O 4 @trp@Ir is an e cient catalyst for reducing nitroaromatics at ambient temperature with a minimal catalyst loading of 0.0025%. The complete conversion of 4-nitrophenol to 4-aminophenol took only 20 seconds with a minimal catalyst loading of 0.0025% and a rate constant of 0.0522 s − 1. The high catalytic activity factor (1.040 s − 1 mg − 1) and high turnover frequency (9 min − 1) obtained for Fe 3 O 4 @trp@Ir nanocatalyst highlight the possible synergistic effect of the two metals (Fe and Ir). The visible-light photocatalytic degradation of 4-NP was also investigated in the presence of Fe 3 O 4 @trp@Ir. The photocatalytic degradation of 4-NP by Fe 3 O 4 @trp@Ir is completed in 20 min with 95.15% e ciency, and the rate of photodegradation of 4-NP (0.1507 min − 1) is about twice the degradation rate of 4-NP in the dark (0.0755 min − 1). The catalyst was recycled and reused for ve cycles without signi cant reduction in the conversion e ciency of the catalyst.