SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "L773:2046 2069 srt2:(2020-2024)"

Sökning: L773:2046 2069 > (2020-2024)

  • Resultat 1-50 av 188
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Abid, Abdul Rahman, et al. (författare)
  • The effect of relative humidity on CaCl2 nanoparticles studied by soft X-ray absorption spectroscopy
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:4, s. 2103-2111
  • Tidskriftsartikel (refereegranskat)abstract
    • Ca- and Cl-containing nanoparticles are common in atmosphere, originating for example from desert dust and sea water. The properties and effects on atmospheric processes of these aerosol particles depend onthe relative humidity (RH) as they are often both hygroscopic and deliquescent. We present here a study of surface structure of free-flying CaCl2 nanoparticles (CaCl2-NPs) in the 100 nm size regime prepared at different humidity levels (RH: 11–85%). We also created mixed nanoparticles by aerosolizing a solution ofCaCl2 and phenylalanine (Phe), which is a hydrophobic amino acid present in atmosphere. Information of hydration state of CaCl2-NPs and production of mixed CaCl2 + Phe nanoparticles was obtained using soft X-ray absorption spectroscopy (XAS) at Ca 2p, Cl 2p, C 1s, and O 1s edges. We also report Ca 2p andCl 2p X-ray absorption spectra of an aqueous CaCl2 solution. The O 1s X-ray absorption spectra measured from hydrated CaCl2-NPs resemble liquid-like water spectrum, which is heavily influenced by the presence of ions. Core level spectra of Ca2+ and Cl- ions do not show a clear dependence of % RH, indicating that the first coordination shell remains similar in all measured hydrated CaCl2-NPs, but they differ from aqueous solution and solid CaCl2.
  •  
2.
  • Aftab, Umair, et al. (författare)
  • Nickel-cobalt bimetallic sulfide NiCo(2)S(4)nanostructures for a robust hydrogen evolution reaction in acidic media
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 10:37, s. 22196-22203
  • Tidskriftsartikel (refereegranskat)abstract
    • There are many challenges associated with the fabrication of efficient, inexpensive, durable and very stable nonprecious metal catalysts for the hydrogen evolution reaction (HER). In this study, we have designed a facile strategy by tailoring the concentration of precursors to successfully obtain nickel-cobalt bimetallic sulfide (NiCo2S4) using a simple hydrothermal method. The morphology of the newly prepared NiCo(2)S(4)comprised a mixture of microparticles and nanorods, which were few microns in dimension. The crystallinity of the composite sample was found to be excellent with a cubic phase. The sample that contained a higher amount of cobalt compared to nickel and produced single-phase NiCo(2)S(4)exhibited considerably improved HER performance. The variation in the salt precursor concentration during the synthesis of a material is a simple methodology to produce a scalable platinum-free catalyst for HER. The advantageous features of the multiple active sites of cobalt in the CN-21 sample as compared to that for pristine CoS and NiS laid the foundation for the provision of abundant active edges for HER. The composite sample produced a current density of 10 mA cm(-2)at an overpotential of 345 mV. Also, it exhibited a Tafel value of 60 mV dec(-1), which predominantly ensured rapid charge transfer kinetics during HER. CN-21 was highly durable and stable for 30 hours. Electrochemical impedance spectroscopy showed that the charge transfer resistance was 21.88 ohms, which further validated the HER polarization curves and Tafel results. CN-21 exhibited a double layer capacitance of 4.69 mu F cm(-2)and a significant electrochemically active surface area of 134.0 cm(2), which again supported the robust efficiency for HER. The obtained results reveal that our developed NiCo(2)S(4)catalyst has a high density of active edges, and it is a non-noble metal catalyst for the hydrogen evolution reaction. The present findings provide an alternative strategy and an active nonprecious material for the development of energy-related applications.
  •  
3.
  • Agbaje, Oluwatoosin B. A., et al. (författare)
  • Characterization of organophosphatic brachiopod shells : spectroscopic assessment of collagen matrix and biomineral components
  • 2020
  • Ingår i: RSC Advances. - 2046-2069. ; 10, s. 38456-38467
  • Tidskriftsartikel (refereegranskat)abstract
    • The shells of linguloid brachiopods such as Lingula and Discinisca are inorganic–organic nanocomposites with a mineral phase of calcium phosphate (Ca-phosphate). Collagen, the main extracellular matrix in Ca-phosphatic vertebrate skeletons, has not previously been clearly resolved at the molecular level in organophosphatic brachiopods. Here, modern and recently-alive linguliform brachiopod shells of Lingula and Discinisca have been studied by microRaman spectroscopy, Fourier transform infrared spectroscopy, field emission gun scanning electron microscopy, and thermal gravimetric analysis. For the first time, biomineralized collagen matrix and Ca-phosphate components were simultaneously identified, showing that the collagen matrix is an important moiety in organophosphatic brachiopod shells, in addition to prevalent chitin. Stabilized nanosized apatitic biominerals (up to ∼50 nm) permeate the framework of organic fibrils. There is a ∼2.5-fold higher wt% of carbonate (CO32−) in Lingula versus Discinisca shells. Both microRaman spectroscopy and infrared spectra show transient amorphous Ca-phosphate and octacalcium phosphate components. For the first time, trivalent moieties at ∼1660 cm−1 and divalent moieties at ∼1690 cm−1 in the amide I spectral region were identified. These are related to collagen cross-links that are abundant in mineralized tissues, and could be important features in the biostructural and mechanical properties of Ca-phosphate shell biominerals. This work provides a critical new understanding of organophosphatic brachiopod shells, which are some of the earliest examples of biomineralization in still-living animals that appeared in the Cambrian radiation.
  •  
4.
  • Aguilar-Sanchez, Andrea, et al. (författare)
  • Charged ultrafiltration membranes based on TEMPO-oxidized cellulose nanofibrils/poly(vinyl alcohol) antifouling coating
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 11:12, s. 6859-6868
  • Tidskriftsartikel (refereegranskat)abstract
    • This study reports the potential of TEMPO-oxidized cellulose nanofibrils (T-CNF)/poly(vinyl alcohol) (PVA) coatings to develop functionalized membranes in the ultrafiltration regime with outstanding antifouling performance and dimensional/pH stability. PVA acts as an anchoring phase interacting with the polyethersulfone (PES) substrate and stabilizing for the hygroscopic T-CNF via crosslinking. The T-CNF/PVA coated PES membranes showed a nano-textured surface, a change in the surface charge, and improved mechanical properties compared to the original PES substrate. A low reduction (4%) in permeance was observed for the coated membranes, attributable to the nanometric coating thickness, surface charge, and hydrophilic nature of the coated layer. The coated membranes exhibited charge specific adsorption driven by electrostatic interaction combined with rejection due to size exclusion (MWCO 530 kDa that correspond to a size of similar to 35-40 nm). Furthermore, a significant reduction in organic fouling and biofouling was found for T-CNF/PVA coated membranes when exposed to BSA and E. coli. The results demonstrate the potential of simple modifications using nanocellulose to manipulate the pore structure and surface chemistry of commercially available membranes without compromising on permeability and mechanical stability.
  •  
5.
  • Albaqami, Munirah D., et al. (författare)
  • The fast nucleation/growth of Co3O4 nanowires on cotton silk : the facile development of a potentiometric uric acid biosensor
  • 2022
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 12:29, s. 18321-18332
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study, we have used cotton silk as a source of abundant hydroxyl groups for the fast nucleation/growth of cobalt oxide (Co3O4) nanowires via a hydrothermal method. The crystal planes of the Co3O4 nanowires well matched the cubic phase. The as-synthesized Co3O4 nanowires mainly contained cobalt and oxygen elements and were found to be highly sensitive towards uric acid in 0.01 M phosphate buffer solution at pH 7.4. Importantly, the Co3O4 nanowires exhibited a large surface area, which was heavily utilized during the immobilization of the enzyme uricase via a physical adsorption method. The potentiometric response of the uricase-immobilizing Co3O4 nanowires was measured in the presence of uric acid (UA) against a silver/silver chloride (Ag/AgCl) reference electrode. The newly fabricated uric acid biosensor possessed a low limit of detection of 1.0 +/- 0.2 nM with a wide linear range of 5 nM to 10 mM and sensitivity of 30.6 mV dec(-1). Additionally, several related parameters of the developed uric acid biosensor were investigated, such as the repeatability, reproducibility, storage stability, selectivity, and dynamic response time, and these were found to be satisfactory. The good performance of the Co3O4 nanowires was verified based on the fast charge-transfer kinetics, as confirmed via electrochemical impedance spectroscopy. The successful practical use of the uric acid biosensor was demonstrated based on the recovery method. The observed performance of the uricase-immobilizing Co3O4 nanowires revealed that they could be considered as a promising and alternative tool for the detection of uric acid under both in vitro and in vivo conditions. Also, the use of cotton silk as a source of abundant hydroxyl groups may be considered for the remarkably fast nucleation/growth of other metal-oxide nanostructures, thereby facilitating the fabrication of functional electrochemical devices, such as batteries, water-splitting devices, and supercapacitors.
  •  
6.
  • Alexandersson, Elin, et al. (författare)
  • Band-selective NMR experiments for suppression of unwanted signals in complex mixtures
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 10, s. 32511-32515
  • Tidskriftsartikel (refereegranskat)abstract
    • Band-selective NMR experiments are presented that allow selective suppression of unwanted signals (SUN) from the spectra of complex metabolite mixtures. As a result, spectral overlap and dynamic range problems are substantially reduced and low-intensity signals normally covered by dominant signals can be observed. The usefulness of the experiments is exemplified with selective suppression of sugar signals from the NMR spectra of fruit juice and a plant sample. Other possible applications include blood, milk, and wine samples.
  •  
7.
  • Ali, Hala R., et al. (författare)
  • Effects of macrophage polarization on gold nanoparticle-assisted plasmonic photothermal therapy
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:40, s. 25047-25056
  • Tidskriftsartikel (refereegranskat)abstract
    • Tumor associated macrophages (TAM) are key pathogenic factors in neoplastic diseases. They are known to have plasticity and can polarize into two opposing phenotypes, including the tumoricidal M1 and the protumoral M2 phenotypes with high prevalence of M2-phentoypes in patients with poor prognosis. Strategies for targeting M2-TAM may consequently increase the efficacy of therapeutic strategies for cancer treatment. Gold nanorod-assisted plasmonic photothermal therapy (PPTT) has emerged as a promising treatment for cancer but the effects of macrophage polarization parameters in the performance of this new treatment modality is still unknown. Herein, human monocytic THP-1 cells were polarized into two opposite phenotypic macrophages (M1-TAM and M2-TAM) and their response to PPTT was examined. M2-TAM exhibits a three-fold increase in AuNP uptake compared to M1-TAM. Laser irradiation results in selective killing of pro-tumoral M2-TAM after treatment with AuNPs with limited effects on anti-tumoral M1-TAM. A positive correlation between the expression of CD206 marker and the AuNP uptake may indicate the role of CD206 in facilitating AuNP uptake. Our findings also suggest that the differences in AuNP avidity and uptake between the M1-TAM and M2-TAM phenotypes may be the rationale behind the effectiveness of PPTT in the treatment of solid tumors.
  •  
8.
  • Alvarez-Asencio, Ruben, et al. (författare)
  • Solventless synthesis of cerium oxide nanoparticles and their application in UV protective clear coatings
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 10:25, s. 14818-14825
  • Tidskriftsartikel (refereegranskat)abstract
    • Colloidal dispersions of cerium oxide nanoparticles are of importance for numerous applications including as catalysts, chemical mechanical polishing agents and additives for UV protective and anticorrosion coatings. Here, concentrated oleate-coated cerium oxide nanoparticles (CeO2 NPs) with a uniform size have been produced by solventless thermolysis of cerium-oleate powder under low pressure at 320 °C and subsequently dispersed in hexane. Unlike any previously reported colloidal synthesis process for ceria nanoparticles, this process does not involve any toxic high boiling point organic solvent that requires subsequent removal at high cost. Although the process is very simple, highly concentrated cerium oxide nanoparticles with more than 17 wt% solid content and 70% of the theoretical yield can be easily obtained. Moreover, the size, shape and crystallinity of cerium oxide nanoparticles can be tailored by changing the thermal decomposition temperature and reaction time. Moreover, the new synthesis route developed in this study allows the synthesis of clean and dispersible ceria nanoparticles at a relatively low cost in a single step. The prepared ceria nanoparticles have an excellent UV absorption property and remain transparent to visible light, thus having the potential to replace potentially hazardous organic compounds in UV absorbing clear coatings. As a proof of concept, the prepared dispersions of cerium oxide nanoparticles in hexane were formulated into a solvent borne binder base to develop clear UV protecting coatings for light sensitive substrates. The general synthesis strategy presented in this study is generally applicable for the low-cost production of a concentrated dispersion of metal oxide nanoparticles with minimal environmental impact.
  •  
9.
  •  
10.
  • Arrhenius, Karine, et al. (författare)
  • Analytical methods for the determination of oil carryover from CNG/biomethane refueling stations recovered in a solvent
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 10:20, s. 11907-11917
  • Tidskriftsartikel (refereegranskat)abstract
    • Vehicle gas is often compressed to about 200 bar at the refueling station prior to charging to the vehicle's tank. If a high amount of oil is carried over to the gas, it may cause damage to the vehicles; it is therefore necessary to accurately measure oil carryover. In this paper, three analytical methods for accurate quantification of the oil content are presented whereby two methods are based on gas chromatography and one on FTIR. To better evaluate the level of complexity of the matrix, 10 different compressor oils in use at different refueling stations were initially collected and analysed with GC and FTIR to identify their analytical traces. The GC traces could be divided into three different profiles: oils exhibiting some well resolved peaks, oils exhibiting globally unresolved peaks with some dominant peaks on top of the hump and oils exhibiting globally unresolved peaks. After selection of three oils; one oil from each type, the three methods were evaluated with regards to the detection and quantification limits, the working range, precision, trueness and robustness. The evaluation of the three measurement methods demonstrated that any of these three methods presented were suitable for the quantification of compressor oil for samples. The FTIR method and the GC/MS method both resulted in measurement uncertainties close to 20% rel. while the GC/FID method resulted in a higher measurement uncertainty (U = 30% rel.).
  •  
11.
  • Auroux, Etienne, et al. (författare)
  • A metal-free and transparent light-emitting device by sequential spray-coating fabrication of all layers including PEDOT:PSS for both electrodes
  • 2023
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 13:25, s. 16943-16951
  • Tidskriftsartikel (refereegranskat)abstract
    • The concept of a metal-free and all-organic electroluminescent device is appealing from both sustainability and cost perspectives. Herein, we report the design and fabrication of such a light-emitting electrochemical cell (LEC), comprising a blend of an emissive semiconducting polymer and an ionic liquid as the active material sandwiched between two poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) conducting-polymer electrodes. In the off-state, this all-organic LEC is highly transparent, and in the on-state, it delivers uniform and fast to turn-on bright surface emission. It is notable that all three device layers were fabricated by material- and cost-efficient spray-coating under ambient air. For the electrodes, we systematically investigated and developed a large number of PEDOT:PSS formulations. We call particular attention to one such p-type doped PEDOT:PSS formulation that was demonstrated to function as the negative cathode, as well as future attempts towards all-organic LECs to carefully consider the effects of electrochemical doping of the electrode in order to achieve optimum device performance.
  •  
12.
  • B. Brant Carvalho, Paulo H., et al. (författare)
  • Structural investigation of three distinct amorphous forms of Ar hydrate
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:49, s. 30744-30754
  • Tidskriftsartikel (refereegranskat)abstract
    • Three amorphous forms of Ar hydrate were produced using the crystalline clathrate hydrate Ar·6.5H2O (structure II, Fd3m, a ≈ 17.1 Å) as a precursor and structurally characterized by a combination of isotope substitution (36Ar) neutron diffraction and molecular dynamics (MD) simulations. The first form followed from the pressure-induced amorphization of the precursor at 1.5 GPa at 95 K and the second from isobaric annealing at 2 GPa and subsequent cooling back to 95 K. In analogy to amorphous ice, these amorphs are termed high-density amorphous (HDA) and very-high-density amorphous (VHDA), respectively. The third amorph (recovered amorphous, RA) was obtained when recovering VHDA to ambient pressure (at 95 K). The three amorphs have distinctly different structures. In HDA the distinction of the original two crystallographically different Ar guests is maintained as differently dense Ar–water hydration structures, which expresses itself in a split first diffraction peak in the neutron structure factor function. Relaxation of the local water structure during annealing produces a homogeneous hydration environment around Ar, which is accompanied with a densification by about 3%. Upon pressure release the homogeneous amorphous structure undergoes expansion by about 21%. Both VHDA and RA can be considered frozen solutions of immiscible Ar and water in which in average 15 and 11 water molecules, respectively, coordinate Ar out to 4 Å. The local water structures of HDA and VHDA Ar hydrates show some analogy to those of the corresponding amorphous ices, featuring H2O molecules in 5- and 6-fold coordination with neighboring molecules. However, they are considerably less dense. Most similarity is seen between RA and low density amorphous ice (LDA), which both feature strictly 4-coordinated H2O networks. It is inferred that, depending on the kind of clathrate structure and occupancy of cages, amorphous states produced from clathrate hydrates display variable local water structures.
  •  
13.
  • Beech, Jason P, et al. (författare)
  • Using symmetry to control viscoelastic waves in pillar arrays
  • 2023
  • Ingår i: RSC Advances. - 2046-2069. ; 13:45, s. 31497-31506
  • Tidskriftsartikel (refereegranskat)abstract
    • Solutions of macromolecules exhibit viscoelastic properties and unlike Newtonian fluids, they may break time-reversal symmetry at low Reynolds numbers resulting in elastic turbulence. Furthermore, under some conditions, instead of the chaotic turbulence, the result is large-scale waves in the form of cyclic spatial and temporal concentration variations, as has been shown for macromolecular DNA flowing in microfluidic pillar arrays. We here demonstrate how altering the symmetry of the individual pillars can be used to influence the symmetry of these waves. We control the extent of instabilities in viscoelastic flow by leveraging the effects of the symmetry of the pillars on the waves, demonstrating suppressed viscoelastic fluctuations with relevance for transport and sorting applications, or conversely opening up for enhanced viscoelasticity-mediated mixing. The onset of waves, which changes flow resistance, occurs at different Deborah numbers for flow in different directions through the array of triangular pillars, thus breaking the symmetry of the flow resistance along the device, opening up for using the occurrence of the waves to construct a fluidic diode.
  •  
14.
  • Ben Chouikha, I., et al. (författare)
  • Quantum chemical study of the reaction paths and kinetics of acetaldehyde formation on a methanol-water ice model
  • 2022
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 12:29, s. 18994-19005
  • Tidskriftsartikel (refereegranskat)abstract
    • Acetaldehyde (CH3CHO) is ubiquitous in interstellar space and is important for astrochemistry as it can contribute to the formation of amino acids through reaction with nitrogen containing chemical species. Quantum chemical and reaction kinetics studies are reported for acetaldehyde formation from the chemical reaction of C(P-3) with a methanol molecule adsorbed at the eighth position of a cubic water cluster. We present extensive quantum chemical calculations for total spin S = 1 and S = 0. The U omega B97XD/6-311++G(2d,p) model chemistry is employed to optimize the structures, compute minimum energy paths and zero-point vibrational energies of all reaction steps. For the optimized structures, the calculated energies are refined by CCSD(T) single point computations. We identify four transition states on the triplet potential energy surface (PES), and one on the singlet PES. The reaction mechanism involves the intermediate formation of CH3OCH adsorbed on the ice cluster. The rate limiting step for forming acetaldehyde is the C-O bond breaking in CH3OCH to form adsorbed CH3 and HCO. We find two positions on the reaction path where spin crossing may be possible such that acetaldehyde can form in its singlet spin state. Using variational transition-state theory with multidimensional tunnelling we provide thermal rate constants for the energetically rate limiting step for both spin states and discuss two routes to acetaldehyde formation. As expected, quantum effects are important at low temperatures.
  •  
15.
  • Benedet, Mattia, et al. (författare)
  • Efficient photoactivated hydrogen evolution promoted by Cu x O-gCN-TiO 2 -Au (x = 1,2) nanoarchitectures
  • 2024
  • Ingår i: RSC Advances. - 2046-2069. ; 14:10, s. 7221-7228
  • Tidskriftsartikel (refereegranskat)abstract
    • In this work, we propose an original and potentially scalable synthetic route for the fabrication of CuxO-gCN-TiO2-Au (x = 1,2) nanoarchitectures, based on Cu foam anodization, graphitic carbon nitride liquid-phase deposition, and TiO2/Au sputtering. A thorough chemico-physical characterization by complementary analytical tools revealed the formation of nanoarchitectures featuring an intimate contact between the system components and a high dispersion of gold nanoparticles. Modulation of single component interplay yielded excellent functional performances in photoactivated hydrogen evolution, corresponding to a photocurrent of ≈−5.7 mA cm−2 at 0.0 V vs. the reversible hydrogen electrode (RHE). These features, along with the very good service life, represent a cornerstone for the conversion of natural resources, as water and largely available sunlight, into added-value solar fuels.
  •  
16.
  • Bhakat, Soumendranath (författare)
  • Pepsin-like aspartic proteases (PAPs) as model systems for combining biomolecular simulation with biophysical experiments
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 11:18, s. 11026-11047
  • Forskningsöversikt (refereegranskat)abstract
    • Pepsin-like aspartic proteases (PAPs) are a class of aspartic proteases which shares tremendous structural similarity with human pepsin. One of the key structural features of PAPs is the presence of a β-hairpin motif otherwise known as flap. The biological function of the PAPs is highly dependent on the conformational dynamics of the flap region. In apo PAPs, the conformational dynamics of the flap is dominated by the rotational degrees of freedom associated withχ1 andχ2 angles of conserved Tyr (or Phe in some cases). However it is plausible that dihedral order parameters associated with several other residues might play crucial roles in the conformational dynamics of apo PAPs. Due to their size, complexities associated with conformational dynamics and clinical significance (drug targets for malaria, Alzheimer's diseaseetc.), PAPs provide a challenging testing ground for computational and experimental methods focusing on understanding conformational dynamics and molecular recognition in biomolecules. The opening of the flap region is necessary to accommodate substrate/ligand in the active site of the PAPs. The BIG challenge is to gain atomistic details into how reversible ligand binding/unbinding (molecular recognition) affects the conformational dynamics. Recent reports of kinetics (Ki,Kd) and thermodynamic parameters (ΔH,TΔS, and ΔG) associated with macro-cyclic ligands bound to BACE1 (belongs to PAP family) provide a perfect challenge (how to deal with big ligands with multiple torsional angles and select optimum order parameters to study reversible ligand binding/unbinding) for computational methods to predict binding free energies and kinetics beyond typical test systemse.g.benzamide-trypsin. In this work, i reviewed several order parameters which were proposed to capture the conformational dynamics and molecular recognition in PAPs. I further highlighted how machine learning methods can be used as order parameters in the context of PAPs. I then proposed some open ideas and challenges in the context of molecular simulation and put forward my case on how biophysical experimentse.g.NMR, time-resolved FRETetc.can be used in conjunction with biomolecular simulation to gain complete atomistic insights into the conformational dynamics of PAPs.
  •  
17.
  • Bhatti, Adeel Liaquat, et al. (författare)
  • Facile doping of nickel into Co3O4 nanostructures to make them efficient for catalyzing the oxygen evolution reaction
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 10:22, s. 12962-12969
  • Tidskriftsartikel (refereegranskat)abstract
    • Designing a facile and low-cost methodology to fabricate earth-abundant catalysts is very much needed for a wide range of applications. Herein, a simple and straightforward approach was developed to tune the electronic properties of cobalt oxide nanostructures by doping them with nickel and then using them to catalyze the oxygen evolution reaction (OER) in an aqueous solution of 1.0 M KOH. The addition of a nickel impurity improved the conductivity of the cobalt oxide, and further increased its activity towards the OER. Analytical techniques such as scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and powder X-ray diffraction (XRD) were used to investigate, respectively, the morphology, composition and crystalline structure of the materials used. The nickel-doped cobalt oxide material showed randomly oriented nanowires and a high density of nanoparticles, exhibited the cubic phase, and contained cobalt, nickel and oxygen as its main elements. The nickel-doped cobalt oxide also yielded a Tafel slope of 82 mV dec(-1) and required an overpotential of 300 mV to reach a current density of 10 mA cm(-2). As an OER catalyst, it was shown to be durable for 40 h. Electrochemical impedance spectroscopy (EIS) analysis showed a low charge-transfer resistance of 177.5 ohms for the nickel-doped cobalt oxide, which provided a further example of its excellent OER performance. These results taken together indicated that nickel doping of cobalt oxide can be accomplished via a facile approach and that the product of this doping can be used for energy and environmental applications.
  •  
18.
  • Blahut, Jan, et al. (författare)
  • Proton-detected fast-magic-angle spinning NMR of paramagnetic inorganic solids
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 11:47, s. 29870-29876
  • Tidskriftsartikel (refereegranskat)abstract
    • Fast (60 kHz) magic angle spinning solid-state NMR allows very sensitive proton detection in highly paramagnetic organometallic powders. We showcase this technique with the complete assignment of H-1 and C-13 resonances in a high-spin Fe(ii) polymerisation catalyst with less than 2 mg of sample at natural abundance.
  •  
19.
  • Blomgren, Fredrik, et al. (författare)
  • Two statins and cromolyn as possible drugs against the cytotoxicity of A beta(31-35) and A beta(25-35) peptides: a comparative study by advanced computer simulation methods
  • 2022
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 12:21, s. 13352-13366
  • Tidskriftsartikel (refereegranskat)abstract
    • In this work, possible effective mechanisms of cromolyn, atorvastatin and lovastatin on the cytotoxicity of A beta(31-35) and A beta(25-35) peptides were investigated by classical molecular dynamics and well-tempered metadynamics simulations. The results demonstrate that all the drugs affect the behavior of the peptides, such as their ability to aggregate, and alter their secondary structures and their affinity to a particular drug. Our findings from the computed properties suggest that the best drug candidate is lovastatin. This medicine inhibits peptide aggregation, adsorbs the peptides on the surface of the drug clusters, changes the secondary structure and binds to MET35, which has been seen as the reason for the toxicity of the studied peptide sequences. Moreover, lovastatin is the drug which previously has demonstrated the strongest ability to penetrate the blood-brain barrier and makes lovastatin the most promising medicine among the three investigated drugs. Atorvastatin is also seen as a potential candidate if its penetration through the blood-brain barrier could be improved. Otherwise, its properties are even better than the ones demonstrated by lovastatin. Cromolyn appears to be less interesting as an anti-aggregant from the computational data, in comparison to the two statins.
  •  
20.
  • Bogaerts, Jonathan, et al. (författare)
  • Employing complementary spectroscopies to study the conformations of an epimeric pair of side-chain stapled peptides in aqueous solution
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:7, s. 4200-4208
  • Tidskriftsartikel (refereegranskat)abstract
    • Understanding the conformational preferences of free ligands in solution is often necessary to rationalize structure–activity relationships in drug discovery. Herein, we examine the conformational behavior of an epimeric pair of side-chain stapled peptides that inhibit the FAD dependent amine oxidase lysine specific demethylase 1 (LSD1). The peptides differ only at a single stereocenter, but display a major difference in binding affinity. Their Raman optical activity (ROA) spectra are most likely dominated by the C-terminus, obscuring the analysis of the epimeric macrocycle. By employing NMR spectroscopy, we show a difference in conformational behavior between the two compounds and that the LSD1 bound conformation of the most potent compound is present to a measurable extent in aqueous solution. In addition, we illustrate that Molecular Dynamics (MD) simulations produce ensembles that include the most important solution conformations, but that it remains problematic to identify relevant conformations with no a priori knowledge from the large conformational pool. Furthermore, this work highlights the importance of understanding the scope and limitations of the available techniques for conducting conformational analyses. It also emphasizes the importance of conformational selection of a flexible ligand in molecular recognition.
  •  
21.
  • Bokale-Shivale, Suvarna, et al. (författare)
  • Synthesis of substituted 3,4-dihydroquinazolinones via a metal free Leuckart-Wallach type reaction
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:1, s. 349-353
  • Tidskriftsartikel (refereegranskat)abstract
    • The 3,4-dihydroquinazolinone (DHQ) moiety is a highly valued scaffold in medicinal chemistry due to the vast number of biologically-active compounds based on this core structure. Current synthetic methods to access these compounds are limited in terms of diversity and flexibility and often require the use of toxic reagents or expensive transition-metal catalysts. Herein, we describe the discovery and development of a novel cascade cyclization/Leuckart–Wallach type strategy to prepare substituted DHQs in a modular and efficient process using readily-available starting materials. Notably, the reaction requires only the addition of formic acid or acetic acid/formic acid and produces H2O, CO2 and methanol as the sole reaction byproducts. Overall, the reaction provides an attractive entry point into this important class of compounds and could even be extended to isotopic labelling via the site-selective incorporation of a deuterium atom.
  •  
22.
  • Bozzola, Tiago, et al. (författare)
  • Direct Sialic Acid 4-OAc Substitution by Nitrogen, Sulfur and Carbon Nucleophiles with Retention of Stereochemistry
  • 2022
  • Ingår i: RSC Advances. - 2046-2069. ; 12:19, s. 11992-11995
  • Tidskriftsartikel (refereegranskat)abstract
    • A direct one-step nucleophilic substitution of the 4-OAc of acetyl protected Neu5Ac is presented. Previously published methods for direct substitution of the 4-OAc are limited to cyclic secondary amines. Here we present conditions that allow for a much wider range of nitrogen nucleophiles as well as thiols and cyanide, to be used. The present investigation significantly broadens the scope of 4-aminations and allows for the introduction of a wide variety of different nucleophiles.
  •  
23.
  •  
24.
  • Buvailo, Halyna I., et al. (författare)
  • Hybrid compound based on diethylenetriaminecopper(ii) cations and scarce V-monosubstituted β-octamolybdate as water oxidation catalyst
  • 2021
  • Ingår i: RSC Advances. - Cambridge : Royal Society of Chemistry. - 2046-2069. ; 11:51, s. 32119-32125
  • Tidskriftsartikel (refereegranskat)abstract
    • Herein, we report on a new hybrid compound (NH4){[Cu(dien)(H2O)2]2[β-VMo7O26]}·1.5H2O (1), where dien = diethylenetriamine, containing an extremely rare mixed-metal pseudo-octamolybdate cluster. An ex situ EPR spectroscopy provided insights into the formation of paramagnetic species in reaction mixture and in solution of 1. The magneto-structural correlations revealed weak antiferromagnetic exchange interactions between the [Cu(dien)]2+ cations transmitted by intermolecular pathways. The cyclic voltammetry showed the one-electron process associated with the Cu3+/Cu2+ oxidation followed by the multi-electron catalytic wave due to water oxidation with a faradaic yield of 86%. The title compound was thus employed in homogeneous water oxidation catalysis using tris(bipyridine)ruthenium photosensitizer. At pH 8.0, efficiency of the catalytic system attained 0.19 turnovers per second supported by the relatively mild water oxidation overpotential of 0.54 V.
  •  
25.
  • Caldararu, Octav, et al. (författare)
  • Water structure in solution and crystal molecular dynamics simulations compared to protein crystal structures
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 10, s. 8435-8443
  • Tidskriftsartikel (refereegranskat)abstract
    • The function of proteins is influenced not only by the atomic structure but also by the detailed structure of the solvent surrounding it. Computational studies of protein structure also critically depend on the water structure around the protein. Herein we compare the water structure obtained from molecular dynamics (MD) simulations of galectin-3 in complex with two ligands to crystallographic water molecules observed in the corresponding crystal structures. We computed MD trajectories both in a water box, which mimics a protein in solution, and in a crystallographic unit cell, which mimics a protein in a crystal. The calculations were compared to crystal structures obtained at both cryogenic and room temperature. Two types of analyses of the MD simulations were performed. First, the positions of the crystallographic water molecules were compared to peaks in the MD density after alignment of the protein in each snapshot. The results of this analysis indicate that all simulations reproduce the crystallographic water structure rather poorly. However, if we define the crystallographic water sites based on their distances to nearby protein atoms and follow these sites throughout the simulations, the MD simulations reproduce the crystallographic water sites much better. This shows that the failure of MD simulations to reproduce the water structure around proteins in crystal structures observed both in this and previous studies is caused by the problem of identifying water sites for a flexible and dynamic protein (traditionally done by overlaying the structures). Our local clustering approach solves the problem and shows that the MD simulations reasonably reproduce the water structure observed in crystals. Furthermore, analysis of the crystal MD simulations indicates a few water molecules that are close to unmodeled electron density peaks in the crystal structures, suggesting that crystal MD could be used as a complementary tool for identifying and modelling water in protein crystallography.
  •  
26.
  • Cao, Zhejian, 1991-, et al. (författare)
  • Calcium/strontium chloride impregnated zeolite A and X granules as optimized ammonia sorbents
  • 2022
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 12:54, s. 35115-35122
  • Tidskriftsartikel (refereegranskat)abstract
    • Calcium chloride (CaCl2) impregnated zeolite A and strontium chloride (SrCl2) impregnated zeolite A and X composite granules were evaluated as ammonia sorbents for automotive selective catalytic reduction systems. The SrCl2-impregnated zeolite A granules showed a 14% increase in ammonia uptake capacity (8.39 mmol g(-1)) compared to zeolite A granules (7.38 mmol g(-1)). Furthermore, composite granules showed 243% faster kinetics of ammonia sorption (0.24 mmol g(-1) min(-1)) compared to SrCl2 (0.07 mmol g(-1) min(-1)) in the first 20 min. The composite CaCl2/SrCl2 impregnated zeolite A granules combined the advantages of the zeolites and CaCl2/SrCl2, where the rapid physisorption from zeolites can reduce the ammonia loading and release time, and chemisorption from the CaCl2/SrCl2 offers abundant ammonia capacity. Moreover, by optimizing the content of SrCl2 loading, the composite granules maintained the granular form with a crushing load of 17 N per granule after ammonia sorption-desorption cycles. Such structurally stable composite sorbents offer an opportunity for fast ammonia loading/release in automotive selective catalytic reduction systems.
  •  
27.
  • Carmona, Pierre, 1995, et al. (författare)
  • Cross-sectional structure evolution of phase-separated spin-coated ethylcellulose/hydroxypropylcellulose films during solvent quenching
  • 2022
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 12:40, s. 26078-26089
  • Tidskriftsartikel (refereegranskat)abstract
    • Porous phase-separated ethylcellulose/hydroxypropylcellulose (EC/HPC) films are used to control drug transport out of pharmaceutical pellets. The films are applied on the pellets using fluidized bed spraying. The drug transport rate is determined by the structure of the porous films that are formed as the water-soluble HPC leaches out. However, a detailed understanding of the evolution of the phase-separated structure during production is lacking. Here, we have investigated EC/HPC films produced by spin-coating, which mimics the industrial manufacturing process. This work aimed to understand the structure formation and film shrinkage during solvent evaporation. The cross-sectional structure evolution was characterized using confocal laser scanning microscopy (CLSM), profilometry and image analysis. The effect of the EC/HPC ratio on the cross-sectional structure evolution was investigated. During shrinkage of the film, the phase-separated structure undergoes a transition from 3D to nearly 2D structure evolution along the surface. This transition appears when the typical length scale of the phase-separated structure is on the order of the thickness of the film. This was particularly pronounced for the bicontinuous systems. The shrinkage rate was found to be independent of the EC/HPC ratio, while the initial and final film thickness increased with increasing HPC fraction. A new method to estimate part of the binodal curve in the ternary phase diagram for EC/HPC in ethanol has been developed. The findings of this work provide a good understanding of the mechanisms responsible for the morphology development and allow tailoring of thin EC/HPC films structure for controlled drug release. 
  •  
28.
  • Chen, Hui, et al. (författare)
  • Refractive index of delignified wood for transparent biocomposites
  • 2020
  • Ingår i: RSC Advances. - 2046-2069. ; 10, s. 40719-40724
  • Tidskriftsartikel (refereegranskat)abstract
    • Refractive index (RI) determination for delignified wood templates is vital for transparent wood composite fabrication. Reported RIs in the literature are based on either single plant fibers or wood powder, measured by the immersion liquid method (ILM) combined with mathematical fitting. However, wood structure complexity and the physical background of the fitting were not considered. In this work, RIs of delignified wood templates were measured by the ILM combined with a light transmission model developed from the Fresnel reflection/refraction theory for composite materials. The RIs of delignified balsa wood are 1.536 ± 0.006 and 1.525 ± 0.008 at the wavelength of 589 nm for light propagating perpendicular and parallel to the wood fiber direction, respectively. For delignified birch wood, corresponding values are 1.537 ± 0.005 and 1.529 ± 0.006, respectively. The RI data for delignified wood scaffolds are important for tailoring optical properties of transparent wood biocomposites, and also vital in optical properties investigations by theoretical modelling of complex light propagation in transparent wood and related composites. The developed light transmission model in combination with the immersion liquid method can be used to determine the RI of complex porous or layered solid materials and composites.
  •  
29.
  • Chen, Hui, et al. (författare)
  • Refractive index of delignified wood for transparent biocomposites
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 10:67, s. 40719-40724
  • Tidskriftsartikel (refereegranskat)abstract
    • Refractive index (RI) determination for delignified wood templates is vital for transparent wood composite fabrication. Reported RIs in the literature are based on either single plant fibers or wood powder, measured by the immersion liquid method (ILM) combined with mathematical fitting. However, wood structure complexity and the physical background of the fitting were not considered. In this work, RIs of delignified wood templates were measured by the ILM combined with a light transmission model developed from the Fresnel reflection/refraction theory for composite materials. The RIs of delignified balsa wood are 1.536 ± 0.006 and 1.525 ± 0.008 at the wavelength of 589 nm for light propagating perpendicular and parallel to the wood fiber direction, respectively. For delignified birch wood, corresponding values are 1.537 ± 0.005 and 1.529 ± 0.006, respectively. The RI data for delignified wood scaffolds are important for tailoring optical properties of transparent wood biocomposites, and also vital in optical properties investigations by theoretical modelling of complex light propagation in transparent wood and related composites. The developed light transmission model in combination with the immersion liquid method can be used to determine the RI of complex porous or layered solid materials and composites.
  •  
30.
  • Chen, Yidong, et al. (författare)
  • Catalytically active and thermally stable core-shell gold-silica nanorods for CO oxidation
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 11:19, s. 11642-11650
  • Tidskriftsartikel (refereegranskat)abstract
    • Deactivation based on sintering phenomena is one of the most costly issues for the industrial application of metal nanoparticle catalysts. To address this drawback, mesoporous silica encapsulation is reported as a promising strategy to stabilize metallic nanoparticles towards use in high temperature catalytic applications. These protective shells provide significant structural support to the nanoparticles, while the mesoporosity allows for efficient transport of the reactants to the catalytically active surface of the metallic nanoparticle in the core. Here, we extend the use of gold nanorods with mesoporous silica shells by investigating their stability in the CO oxidation reaction as an example of high temperature gas phase catalysis. Gold nanorods were chosen as the model system due to the availability of a simple, high yield synthesis method for both the metallic nanorods and the mesoporous silica shells. We demonstrate the catalytic activity of gold nanorods with mesoporous silica shells at temperatures up to 350 degrees C over several cycles, as well as the thermal stability up to 500 degrees C, and compare these results to surfactant-stabilized gold nanorods of similar size, which degrade, and lose most of their catalytic activity, before reaching 150 degrees C. These results show that the gold nanorods protected by the mesoporous silica shells have a significantly higher thermal stability than surfactant-stabilized gold nanorods and that the mesoporous silica shell allows for stable catalytic activity with little degradation at high temperatures.
  •  
31.
  •  
32.
  • Chintha, C., et al. (författare)
  • Molecular modeling provides a structural basis for PERK inhibitor selectivity towards RIPK1
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 10:1, s. 367-375
  • Tidskriftsartikel (refereegranskat)abstract
    • Protein kinases are crucial drug targets in cancer therapy. Kinase inhibitors are promiscuous in nature due to the highly conserved nature of the kinase ATP binding pockets. PERK has emerged as a potential therapeutic target in cancer. However, PERK inhibitors GSK2606414 and GSK2656157 also target RIPK1 whereas AMG44 is more specific to PERK. To understand the structural basis for the selectivity of PERK ligands to RIPK1 we have undertaken a detailed in silico analysis using molecular docking followed by molecular dynamics simulations to explore the selectivity profiles of the compounds. Although the binding sites of PERK and RIPK1 are similar, their binding response to small molecules is different. The docking models revealed a common binding mode for GSK2606414 and GSK2656157 in the RIPK1 binding site, similar to its cognate ligand. In contrast, AMG44 had a strikingly different predicted binding profile in the RIPK1 binding site with both rigid docking and induced fit docking settings. Our study shows a molecular mechanism responsible for dual targeting by the GSK ligands. More broadly, this work illustrates the potential of molecular docking to correctly predict the binding towards different kinase structures, and will aid in the design of selective PERK kinase inhibitors.
  •  
33.
  • Colas, Kilian, et al. (författare)
  • Indolylbenzothiadiazoles as highly tunable fluorophores for imaging lipid droplet accumulation in astrocytes and glioblastoma cells
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:39, s. 23960-23967
  • Tidskriftsartikel (refereegranskat)abstract
    • We present an extensive photophysical study of a series of fluorescent indolylbenzothiadiazole derivatives and their ability to specifically image lipid droplets in astrocytes and glioblastoma cells. All compounds in the series displayed positive solvatochromism together with large Stokes shifts, and π-extended derivatives exhibited elevated brightness. It was shown that the fluorescence properties were highly tunable by varying the electronic character or size of the N-substituent on the indole motif. Three compounds proved capable as probes for detecting small quantities of lipid deposits in healthy and cancerous brain cells. In addition, all twelve compounds in the series were predicted to cross the blood–brain barrier, which raises the prospect for future in vivo studies for exploring the role of lipid droplets in the central nervous system.
  •  
34.
  • Coroaba, Adina, et al. (författare)
  • Probing the supramolecular features via π–π interaction of a di-iminopyrene-di-benzo-18-crown-6-ether compound : experimental and theoretical study
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 10:63, s. 38304-38315
  • Tidskriftsartikel (refereegranskat)abstract
    • A novel DPyDB-CN-18C6 compound was synthesised by linking a pyrene moiety to each phenyl group of dibenzo-18-crown-6-ether, the crown ether, through –HCN– bonds and characterized by FTIR, 1H-NMR, 13C-NMR, TGA, and DSC techniques. The quantitative 13C-NMR analysis revealed the presence of two position isomers. The electronic structure of the DPyDB-CN-18C6 molecule was characterized by UV-vis and fluorescence spectroscopies in four solvents with different polarities to observe particular behavior of isomers, as well as to demonstrate a possible non-bonding chemical association (such as ground- and excited-state associations, namely, to probe if there were forming dimers/excimers). The interpretation of the electronic structure was realized through QM calculations. The TD-CAM-B3LYP functional, at the 6-311+G(d,p) basis set, indicated the presence of predominant π → π* and mixed π → π* + n → π* transitions, in line with the UV-vis experimental data. Even though DPyDB-CN-18C6 computational studies revealed a π-extended conjugation effect with predominantly π → π* transitions, thorough fluorescence analysis was observed a weak emission, as an effect of PET and ACQ. In particular, the WAXD analysis of powder and thin films obtained from n-hexane, 1,2-dichloroethane, and ethanol indicated an amorphous organization, whereas from toluene a smectic ordering was obtained. These results were correlated with MD simulation, and it was observed that the molecular geometry of DPyDB-CN-18C6 molecule played a defining role in the pyrene stacking arrangement.
  •  
35.
  • Correia, Mario S. P., et al. (författare)
  • Investigation of the individual human sulfatome in plasma and urine samples reveals an age-dependency
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:55, s. 34788-34794
  • Tidskriftsartikel (refereegranskat)abstract
    • Metabolic microbiome interaction with the human host has been linked to human physiology and disease development. The elucidation of this interspecies metabolite exchange will lead to identification of beneficial metabolites and disease modulators. Their discovery and quantitative analysis requires the development of specific tools and analysis of specific compound classes. Sulfated metabolites are considered a readout for the co-metabolism of the microbiome and their host. This compound class is part of the human phase II clearance process of xenobiotics and is the main focus in drug or doping metabolism and also includes dietary components and microbiome-derived compounds. Here, we report the targeted analysis of sulfated metabolites in plasma and urine samples in the same individuals to identify the core sulfatome and similarities between these two sample types. This analysis of 27 individuals led to the identification of the core sulfatome of 41 metabolites in plasma and urine samples as well as an age effect for 15 metabolites in both sample types.
  •  
36.
  • Das, Atanu Kumar, et al. (författare)
  • Raw natural rubber latex-based bio-adhesive for the production of particleboard: formulation and optimization of process parameters
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 11, s. 28542-28549
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study, bio-adhesives from natural rubber latex (NRL) were combined with starch and formic acid to fabricate jute stick-based particleboards (JSPs). Different blends of NRL, starch, and formic acid, i.e., 6 : 1 : 1, 2 : 1 : 1, and 2 : 3 : 3, were used to produce particleboards using a pressing temperature of 180 °C and applied pressure of 5 MPa using a 5 min pressing time. The particleboards were tested for physical, mechanical, and thermal properties according to ANSI standards. Based on initial screening, the best formula (NRL/starch/formic acid of 2 : 3 : 3) was used to optimize the temperature and pressing time for the highest board performance. The highest density, tensile strength, modulus of elasticity, and modulus of rupture were 830 g cm−3, 10.51, 2380, and 20.05 N mm−2, respectively. Thermo-gravimetric analysis indicated that thermal decomposition of samples primarily occurred in a temperature range of 265 to 399 °C, indicating good thermal performance. The measured physical and mechanical properties of the produced JSPs fulfilled the production standards. However, fulfilling the water absorption and thickness swelling criteria was a challenge. The results indicate that NRL is a promising alternative binder when blended with starch and formic acid.
  •  
37.
  • Das, Atanu Kumar, et al. (författare)
  • Raw natural rubber latex-based bio-adhesive for the production of particleboard: formulation and optimization of process parameters
  • 2021
  • Ingår i: RSC Advances. - 2046-2069. ; 11, s. 28542 –28549-
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study, bio-adhesives from natural rubber latex (NRL) were combined with starch and formic acid to fabricate jute stick-based particleboards (JSPs). Different blends of NRL, starch, and formic acid, i.e., 6 : 1 : 1, 2 : 1 : 1, and 2 : 3 : 3, were used to produce particleboards using a pressing temperature of 180 °C and applied pressure of 5 MPa using a 5 min pressing time. The particleboards were tested for physical, mechanical, and thermal properties according to ANSI standards. Based on initial screening, the best formula (NRL/starch/formic acid of 2 : 3 : 3) was used to optimize the temperature and pressing time for the highest board performance. The highest density, tensile strength, modulus of elasticity, and modulus of rupture were 830 g cm−3, 10.51, 2380, and 20.05 N mm−2, respectively. Thermo-gravimetric analysis indicated that thermal decomposition of samples primarily occurred in a temperature range of 265 to 399 °C, indicating good thermal performance. The measured physical and mechanical properties of the produced JSPs fulfilled the production standards. However, fulfilling the water absorption and thickness swelling criteria was a challenge. The results indicate that NRL is a promising alternative binder when blended with starch and formic acid.
  •  
38.
  • De Oliveira Maciel, Ayanne, et al. (författare)
  • Enzyme-accelerated CO2 capture and storage (CCS) using paper and pulp residues as co-sequestrating agents
  • 2024
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 14:9, s. 6443-6461
  • Tidskriftsartikel (refereegranskat)abstract
    • In the present work, four CaCO3-rich solid residues from the pulp and paper industry (lime mud, green liquor sludge, electrostatic precipitator dust, and lime dregs) were assessed for their potential as co-sequestrating agents in carbon capture. Carbonic anhydrase (CA) was added to promote both CO2 hydration and residue mineral dissolution, offering an enhancement in CO2-capture yield under atmospheric (up to 4-fold) and industrial-gas mimic conditions (up to 2.2-fold). Geological CO2 storage using olivine as a reference material was employed in two stages: one involving mineral dissolution, with leaching of Mg2+ and SiO2 from olivine; and the second involving mineral carbonation, converting Mg2+ and bicarbonate to MgCO3 as a permanent storage form of CO2. The results showed an enhanced carbonation yield up to 6.9%, when CA was added in the prior CO2-capture step. The proposed route underlines the importance of the valorization of industrial residues toward achieving neutral, or even negative emissions in the case of bioenergy-based plants, without the need for energy-intensive compression and long-distance transport of the captured CO2. This is a proof of concept for an integrated strategy in which a biocatalyst is applied as a CO2-capture promoter while CO2 storage can be done near industrial sites with adequate geological characteristics.
  •  
39.
  • Deiana, Luca, et al. (författare)
  • Subtilisin integrated artificial plant cell walls as heterogeneous catalysts for asymmetric synthesis of (S)-amides
  • 2023
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 13:29, s. 19975-19980
  • Tidskriftsartikel (refereegranskat)abstract
    • Subtilisin integrated artificial plant-cell walls (APCWs) were fabricated by self-assembly using cellulose or nanocellulose as the main component. The resulting APCW catalysts are excellent heterogeneous catalysts for the asymmetric synthesis of (S)-amides. This was demonstrated by the APCW-catalyzed kinetic resolution of several racemic primary amines to give the corresponding (S)-amides in high yields with excellent enantioselectivity. The APCW catalyst can be recycled for multiple reaction cycles without loss of enantioselectivity. The assembled APCW catalyst was also able to cooperate with a homogeneous organoruthenium complex, which allowed for the co-catalytic dynamic kinetic resolution (DKR) of a racemic primary amine to give the corresponding (S)-amide in high yield. The APCW/Ru co-catalysis constitutes the first examples of DKR of chiral primary amines when subtilisin is used as a co-catalyst.
  •  
40.
  • Doloczki, Susanne, et al. (författare)
  • Photophysical characterization and fluorescence cell imaging applications of 4-N-substituted benzothiadiazoles
  • 2022
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 12:23, s. 14544-14550
  • Tidskriftsartikel (refereegranskat)abstract
    • In this work, a series of fluorescent 2,1,3-benzothiadiazole derivatives with various N-substituents in the 4- position was synthesized and photophysically characterized in various solvents. Three compounds emerged as excellent fluorescent probes for imaging lipid droplets in cancer cells. A correlation between their high lipophilicity and lipid droplet specificity could be found, with log P ≥ 4 being characteristic for lipid droplet accumulation.
  •  
41.
  • Doyle, Bradley, et al. (författare)
  • Immobilised-enzyme microreactors for the identification and synthesis of conjugated drug metabolites
  • 2023
  • Ingår i: RSC Advances. - 2046-2069. ; 13:40, s. 27696-27704
  • Tidskriftsartikel (refereegranskat)abstract
    • The study of naturally circulating drug metabolites has been a focus of interest, since these metabolites may have different therapeutic and toxicological effects compared to the parent drug. The synthesis of metabolites outside of the human body is vital in order to conduct studies into the pharmacological activities of drugs and bioactive compounds. Current synthesis methods require significant purification and separation efforts or do not provide sufficient quantities for use in pharmacology experiments. Thus, there is a need for simple methods yielding high conversions whilst bypassing the requirement for a separation. Here we have developed and optimised flow chemistry methods in glass microfluidic reactors utilising surface-immobilised enzymes for sulfonation (SULT1a1) and glucuronidation (UGT1a1). Conversion occurs in flow, the precursor and co-factor are pumped through the device, react with the immobilised enzymes and the product is then simply collected at the outlet with no separation from a complex biological matrix required. Conversion only occurred when both the correct co-factor and enzyme were present within the microfluidic system. Yields of 0.97 & PLUSMN; 0.26 & mu;g were obtained from the conversion of resorufin into resorufin sulfate over 2 h with the SULT1a1 enzyme and 0.47 & mu;g of resorufin glucuronide over 4 h for UGT1a1. This was demonstrated to be significantly more than static test tube reactions at 0.22 & mu;g (SULT1a1) and 0.19 & mu;g (UGT1a1) over 4 h. With scaling out and parallelising, useable quantities of hundreds of micrograms for use in pharmacology studies can be synthesised simply. On-chip continuous-flow synthesis of metabolites from glucuronidation and sulfonation reactions to enable synthesis of analytical standards and study drug metabolism.
  •  
42.
  • Ekström, Erik, et al. (författare)
  • The effects of microstructure, Nb content and secondary Ruddlesden-Popper phase on thermoelectric properties in perovskite CaMn1-xNbxO3 (x=0-0.10) thin films
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 10:13, s. 7918-7926
  • Tidskriftsartikel (refereegranskat)abstract
    • CaMn1-xNbxO3 (x = 0, 0.5, 0.6, 0.7 and 0.10) thin films have been grown by a two-step sputtering/annealing method. First, rock-salt-structured (Ca,Mn1-x,Nb-x)O thin films were deposited on 11 & x304;00 sapphire using reactive RF magnetron co-sputtering from elemental targets of Ca, Mn and Nb. The CaMn1-xNbxO3 films were then obtained by thermally induced phase transformation from rock-salt-structured (Ca,Mn1-xNbx)O to orthorhombic during post-deposition annealing at 700 degrees C for 3 h in oxygen flow. The X-ray diffraction patterns of pure CaMnO3 showed mixed orientation, while Nb-containing films were epitaxially grown in [101] out of-plane-direction. Scanning transmission electron microscopy showed a Ruddlesden-Popper (R-P) secondary phase in the films, which results in reduction of the electrical and thermal conductivity of CaMn1-xNbxO3. The electrical resistivity and Seebeck coefficient of the pure CaMnO3 film were measured to 2.7 omega cm and -270 mu V K-1 at room temperature, respectively. The electrical resistivity and Seebeck coefficient were reduced by alloying with Nb and was measured to 0.09 omega cm and -145 mu V K-1 for x = 0.05. Yielding a power factor of 21.5 mu W K-2 m(-1) near room temperature, nearly eight times higher than for pure CaMnO3 (2.8 mu W K-2 m(-1)). The power factors for alloyed samples are low compared to other studies on phase-pure material. This is due to high electrical resistivity originating from the secondary R-P phase. The thermal conductivity of the CaMn1-xNbxO3 films is low for all samples and is the lowest for x = 0.07 and 0.10, determined to 1.6 W m(-1) K-1. The low thermal conductivity is attributed to grain boundary scattering and the secondary R-P phase.
  •  
43.
  • Ergun Dönmez, Merve, 1986-, et al. (författare)
  • Analytical and preparative separation and isolation of functionalized fullerenes by conventional HPLC stationary phases : method development and column screening
  • 2020
  • Ingår i: RSC Advances. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 10:33, s. 19211-19218
  • Tidskriftsartikel (refereegranskat)abstract
    • Isolation and purification of functionalized fullerenes from often complex reaction mixtures is challenging due to the hydrophobic nature and low solubility in regular organic solvents. We have developed an HPLC method that efficiently, employing regular reversed phase stationary phases, separates not only C-60 from C-70 in a model mixture, but also C-60 monoadducts from polyadducts and unreacted C-60 from fulleropyrrolidine and hydroarylation example reaction mixtures. Six HPLC columns with regular reversed phase stationary phases were evaluated using varying proportions of acetonitrile in toluene as eluent; with C18 and C12 stationary phases with high surface area (450-400 m(2) g(-1)) being the most efficient regarding separation efficiency and analysis time for all mixtures. The analytical method is effectively transferrable to a preparative scale to isolate the monoaddition products from complex fullerene reaction mixtures.
  •  
44.
  • Ermilova, Inna, 1983-, et al. (författare)
  • Modelling of interactions between Aβ(25-35) peptide and phospholipid bilayers : effects of cholesterol and lipid saturation
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 10:7, s. 3902-3915
  • Tidskriftsartikel (refereegranskat)abstract
    • Aggregation of amyloid beta (Aβ) peptides in neuronal membranes is a known promoter of Alzheimer’s disease. To gain insight into the molecular details of Aβ peptide aggregation and its effect on model neuronal membranes, we carried out molecular dynamics simulations of the Aβ(25–35) fragment of the amyloid precursor protein in phospholipid bilayers composed of either fully saturated or highly unsaturated lipids, in the presence or absence of cholesterol. It was found that the peptide does not penetrate through any of the considered membranes, but can reside in the headgroup region and upper part of the lipid tails showing a clear preference to a polyunsaturated cholesterol-free membrane. Due to the ordering and condensing effect upon addition of cholesterol, membranes become more rigid facilitating peptide aggregation on the surface. Except for the case of the cholesterol-free saturated lipid bilayer, the peptides have a small effect on the membrane structure and ordering. It was also found that the most “active” amino-acid for peptide–lipid and peptide–cholesterol interaction is methionine-35, followed by asparagine-27 and serine-26, which form hydrogen bonds between peptides and polar atoms of lipid headgroups. These amino acids are also primarily responsible for peptide aggregation. This work will be relevant for designing strategies to develop drugs to combat Alzheimer’s disease.
  •  
45.
  • Esquivel-Pena, Vicente, et al. (författare)
  • Hybrids based on borate-functionalized cellulose nanofibers and noble-metal nanoparticles as sustainable catalysts for environmental applications
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 10:21, s. 12460-12468
  • Tidskriftsartikel (refereegranskat)abstract
    • Polymeric supports from renewable resources such as cellulose nanomaterials are having a direct impact on the development of heterogenous sustainable catalysts. Recently, to increase the potentiality of these materials, research has been oriented towards novel functionalization possibilities. In this study, to increase the stability of cellulose nanofiber films as catalytic supports, by limiting the solubility in water, we report the synthesis of new hybrid catalysts (HC) based on silver, gold, and platinum nanoparticles, and the corresponding bimetallic nanoparticles, supported on cellulose nanofibers (CNFs) cross-linked with borate ions. The catalysts were prepared from metal precursors reduced by the CNFs in an aqueous suspension. Metal nanoparticles supported on CNFs with a spherical shape and a mean size of 9 nm were confirmed by TEM, XRD, and SAXS. Functionalized films of HC-CNFs were obtained by adding a borate solution as a cross-linking agent. Solid-state B-11 NMR of films with different cross-linking degrees evidenced the presence of four different boron species of which the bis-chelate is responsible for the cross-linking of the CNFs. Also, it may be concluded that the bis-chelate and the mono-chelates modify the microstructure of the film increasing the water uptake and enhancing the catalytic activity in the reduction of 4-nitrophenol.
  •  
46.
  • Fadaei Naeini, Vahid, Postdoctoral Researcher, 1988-, et al. (författare)
  • Decisive structural elements in water and ion permeation through mechanosensitive channels of large conductance: insights from molecular dynamics simulation
  • 2022
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 12:28, s. 17803-17816
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, a series of equilibrium molecular dynamics simulations (EMD), steered molecular dynamics (SMD), and computational electrophysiology methods are carried out to explore water and ion permeation through mechanosensitive channels of large conductance (MscL). This research aims to identify the pore-lining side chains of the channel in different conformations of MscL homologs by analyzing the pore size. The distribution of permeating water dipole angles through the pore domains enclosed by VAL21 and GLU104 demonstrated that water molecules are oriented toward the charged oxygen headgroups of GLU104 from their hydrogen atoms to retain this interaction in a stabilized fashion. Although, this behavior was not perceived for VAL21. Numerical assessments of the secondary structure clarified that, during the ion permeation, in addition to the secondary structure alterations, the structure of Tb-MscL would also undergo significant conformational changes. It was elucidated that VAL21, GLU104, and water molecules accomplish a fundamental task in ion permeation. The mentioned residues hinder ion permeation so that the pulling SMD force is increased remarkably when the ions permeate through the domains enclosed by VAL21 and GLU102. The hydration level and potassium diffusivity in the hydrophobic gate of the transmembrane domain were promoted by applying the external electric field. Furthermore, the implementation of an external electric field altered the distribution pattern for potassium ions in the system while intensifying the accumulation of Cl− in the vicinity of ARG11 and ARG98.
  •  
47.
  • Faisal, Ayad A. H, et al. (författare)
  • Controlling metal ion migration in contaminated groundwater with Iraqi clay barriers for water resource protection
  • 2023
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 13:24, s. 16196-16205
  • Tidskriftsartikel (refereegranskat)abstract
    • This study investigates the effectiveness of using Iraqi clay as a low-permeability layer to prevent the migration of lead and nickel ions in groundwater-aquifers. Tests of batch operation have been conducted to determine the optimal conditions for removing Pb2+ ions, which were found to be 120 minutes of contact time, a pH of 5, 0.12 g of clay per 100 mL of solution, and an agitation of 250 rpm. These conditions resulted in a 90% removal efficiency for a 50 mg L−1 initial concentration of lead ions. To remove nickel ions with an efficiency of 80%, the optimal conditions were 60 minutes of contact time, a pH of 6, 12 g of clay per 100 mL of solution, and an agitation of 250 rpm. Several sorption models were evaluated, and the Langmuir formula was found to be the most effective. The highest sorption capacities were 1.75 and 137 mg g−1 for nickel and lead ions, respectively. The spread of metal ions was simulated using finite element analysis in the COMSOL multiphysics simulation software, taking into account the presence of a clay barrier. The results showed that the barrier creates low-discharge zones along the down-gradient of the barrier, reducing the rate of pollutant migration to protect the water sources.
  •  
48.
  • Fan, Junpeng, et al. (författare)
  • Solid-state synthesis of few-layer cobalt-doped MoS2 with CoMoS phase on nitrogen-doped graphene driven by microwave irradiation for hydrogen electrocatalysis
  • 2020
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 10:56, s. 34323-34332
  • Tidskriftsartikel (refereegranskat)abstract
    • The high catalytic activity of cobalt-doped MoS2 (Co–MoS2) observed in several chemical reactions such as hydrogen evolution and hydrodesulfurization, among others, is mainly attributed to the formation of the CoMoS phase, in which Co occupies the edge-sites of MoS2. Unfortunately, its production represents a challenge due to limited cobalt incorporation and considerable segregation into sulfides and sulfates. We, therefore, developed a fast and efficient solid-state microwave irradiation synthesis process suitable for producing thin Co–MoS2 flakes (∼3–8 layers) attached on nitrogen-doped reduced graphene oxide. The CoMoS phase is predominant in samples with up to 15 at% of cobalt, and only a slight segregation into cobalt sulfides/sulfates is noticed at larger Co content. The Co–MoS2 flakes exhibit a large number of defects resulting in wavy sheets with significant variations in interlayer distance. The catalytic performance was investigated by evaluating the activity towards the hydrogen evolution reaction (HER), and a gradual improvement with increased amount of Co was observed, reaching a maximum at 15 at% with an overpotential of 197 mV at −10 mA cm−2, and a Tafel slope of 61 mV dec−1. The Co doping had little effect on the HER mechanism, but a reduced onset potential and charge transfer resistance contributed to the improved activity. Our results demonstrate the feasibility of using a rapid microwave irradiation process to produce highly doped Co–MoS2 with predominant CoMoS phase, excellent HER activity, and operational stability.
  •  
49.
  • Fijoł, Natalia, et al. (författare)
  • 3D-printed monolithic biofilters based on a polylactic acid (PLA) - hydroxyapatite (HAp) composite for heavy metal removal from an aqueous medium
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 11:51, s. 32408-32418
  • Tidskriftsartikel (refereegranskat)abstract
    • High flux, monolithic water purification filters based on polylactic acid (PLA) functionalised with fish scale extracted hydroxyapatite (HAp) were prepared by solvent-assisted blending and thermally induced phase separation (TIPS), followed by twin-screw extrusion into filaments and processed via three-dimensional (3D) printing. The printed filters with consistent pore geometry and channel interconnectivity as well as homogenous distribution of HAp in the PLA matrix showed adsorption capabilities towards heavy metals i.e. cadmium (Cd) and lead (Pb) with maximum adsorption capacity of 112.1 mg gHAp−1 and 360.5 mg gHAp−1 for the metal salt of Pb and Cd, respectively. The adsorption was found to be driven by a combination of ion exchange, dissolution and precipitation on HAp and surface complexation.
  •  
50.
  • FitzGerald, Edward A., et al. (författare)
  • Discovery of fragments inducing conformational effects in dynamic proteins using a second-harmonic generation biosensor
  • 2021
  • Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:13, s. 7527-7537
  • Tidskriftsartikel (refereegranskat)abstract
    • Biophysical screening of compound libraries for the identification of ligands that interact with a protein is efficient, but does typically not reveal if (or how) ligands may interfere with its functional properties. For this a biochemical/functional assay is required. But for proteins whose function is dependent on a conformational change, such assays are typically complex or have low throughput. Here we have explored a high-throughput second-harmonic generation (SHG) biosensor to detect fragments that induce conformational changes upon binding to a protein in real time and identify dynamic regions. Multiwell plate format SHG assays were developed for wild-type and six engineered single-cysteine mutants of acetyl choline binding protein (AChBP), a homologue to ligand gated ion channels (LGICs). They were conjugated with second harmonic-active labels via amine or maleimide coupling. To validate the assay, it was confirmed that the conformational changes induced in AChBP by nicotinic acetyl choline receptor (nAChR) agonists and antagonists were qualitatively different. A 1056 fragment library was subsequently screened against all variants and conformational modulators of AChBP were successfully identified, with hit rates from 9–22%, depending on the AChBP variant. A subset of four hits was selected for orthogonal validation and structural analysis. A time-resolved grating-coupled interferometry-based biosensor assay confirmed the interaction to be a reversible 1-step 1 : 1 interaction, and provided estimates of affinities and interaction kinetic rate constants (KD = 0.28–63 μM, ka = 0.1–6 μM−1 s−1, kd = 1 s−1). X-ray crystallography of two of the fragments confirmed their binding at a previously described conformationally dynamic site, corresponding to the regulatory site of LGICs. These results reveal that SHG has the sensitivity to identify fragments that induce conformational changes in a protein. A selection of fragment hits with a response profile different to known LGIC regulators was characterized and confirmed to bind to dynamic regions of the protein.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-50 av 188
Typ av publikation
tidskriftsartikel (177)
forskningsöversikt (11)
Typ av innehåll
refereegranskat (186)
övrigt vetenskapligt/konstnärligt (2)
Författare/redaktör
Tahira, Aneela (5)
Ibupoto, Zafar Hussa ... (4)
Mathew, Aji P. (4)
Aftab, Umair (4)
Akhtar, Farid (4)
Tenje, Maria (3)
visa fler...
Nicholls, Ian A. (3)
Agar, David (3)
Rudolfsson, Magnus (3)
Larsson, Sylvia (3)
Vigolo, Brigitte (3)
Slabon, Adam (2)
Andersson, Martin (2)
Bhattacharya, Prosun ... (2)
Willander, Magnus (2)
Lidin, Sven (2)
Ahuja, Rajeev, 1965- (2)
Abdelhamid, Hani Nas ... (2)
Lendel, Christofer (2)
Ellervik, Ulf (2)
Hellman, Anders, 197 ... (2)
Swartling, Fredrik J ... (2)
Ågren, Hans (2)
Nierstrasz, Vincent, ... (2)
Abro, Muhammad Ishaq (2)
Bhatti, Adeel Liaqua ... (2)
Nafady, Ayman (2)
Seisenbaeva, Gulaim (2)
Christakopoulos, Pau ... (2)
Guan, Jinping (2)
Behary, Nemeshwaree (2)
Barbe, Laurent (2)
Rova, Ulrika (2)
Ermilova, Inna, 1983 (2)
Sun, Licheng, 1962- (2)
Olsson, Richard (2)
Olsson, Eva, 1960 (2)
Beech, Jason P. (2)
Tegenfeldt, Jonas O. (2)
Benskin, Jonathan P. (2)
Hedenqvist, Mikael S ... (2)
Popov, Sergei (2)
Leifer, Klaus, 1965- (2)
Strömberg, Roger (2)
Wang, Ergang, 1981 (2)
Carlesso, Antonio, 1 ... (2)
Eriksson, Leif A, 19 ... (2)
Chen, Hui (2)
Mahdizadeh, Sayyed J ... (2)
Govender, T (2)
visa färre...
Lärosäte
Uppsala universitet (33)
Kungliga Tekniska Högskolan (27)
Chalmers tekniska högskola (23)
Stockholms universitet (22)
Lunds universitet (22)
Linköpings universitet (19)
visa fler...
Umeå universitet (14)
Luleå tekniska universitet (14)
Karolinska Institutet (10)
RISE (9)
Göteborgs universitet (7)
Sveriges Lantbruksuniversitet (7)
Malmö universitet (4)
Mittuniversitetet (3)
Linnéuniversitetet (3)
Högskolan i Borås (2)
Karlstads universitet (2)
Högskolan i Halmstad (1)
visa färre...
Språk
Engelska (188)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (149)
Teknik (37)
Medicin och hälsovetenskap (19)
Lantbruksvetenskap (4)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy