Nanocellulose, a nanoscale derivative from renewable biomass sources, possesses remarkable colloidal properties in water, mechanical strength, and biocompatibility. It emerges as a promising ...bio-based dispersing agent for various nanomaterials in water. This mini-review explores the interaction between cellulose nanomaterials (nanocrystals or nanofibers) and water, elucidating how this may enable their potential as an eco-friendly dispersing agent. We explore the potential of nanocellulose derived from top-down processes, nanocrystals, and nanofibers for dispersing carbon nanomaterials, semiconducting oxide nanoparticles, and other nanomaterials in water. We also highlight its advantages over traditional methods by not only effectively dispersing those nanomaterials but also potentially eliminating the need for further chemical treatments or supporting stabilizers. This not only preserves the exceptional properties of nanomaterials in aqueous dispersion, but may even lead to the emergence of novel hybrid functionalities. Overall, this mini-review underscores the remarkable versatility of nanocellulose as a green dispersing agent for a variety of nanomaterials, inspiring further research to expand its potential to other nanomaterials and applications.
The distribution and roles of the cannabinoid CB
2
receptor in the CNS are still a matter of debate. Recent data suggest that, in addition to its presence in microglial cells, the CB
2
receptor may ...be also expressed at low levels, yet biologically relevant, in other cell types such as neurons. It is accepted that the expression of CB
2
receptors in the CNS is low under physiological conditions and is significantly elevated in chronic neuroinflammatory states associated with neurodegenerative diseases such as Alzheimer’s disease. By using a novel mouse model (CB
2
EGFP/f/f
), we studied the distribution of cannabinoid CB
2
receptors in the 5xFAD mouse model of Alzheimer’s disease (by generating 5xFAD/CB
2
EGFP/f/f
mice) and explored the roles of CB
2
receptors in microglial function. We used a novel selective and brain penetrant CB
2
receptor agonist (RO6866945) as well as mice lacking the CB
2
receptor (5xFAD/CB
2
−/−
) for these studies. We found that CB
2
receptors are expressed in dystrophic neurite-associated microglia and that their modulation modifies the number and activity of microglial cells as well as the metabolism of the insoluble form of the amyloid peptide. These results support microglial CB
2
receptors as potential targets for the development of amyloid-modulating therapies.
Tacrolimus (TAC) is a narrow-therapeutic-range immunosuppressant drug used after organ transplantation. A therapeutic failure is possible if drug levels are not within the therapeutic range after the ...first year of treatment. Pharmacogenetic variants and drug–drug interactions (DDIs) are involved. We describe a patient case of a young man (16 years old) with a renal transplant receiving therapy including TAC, mycophenolic acid (MFA), prednisone and omeprazole for prophylaxis of gastric and duodenal ulceration. The patient showed great fluctuation in TAC blood concentration/oral dose ratio, as well as pharmacotherapy adverse effects (AEs) and frequent diarrhea episodes. Additionally, decreased kidney function was found. A pharmacotherapeutic follow-up, including pharmacogenetic analysis, was carried out. The selection of the genes studied was based on the previous literature (CYP3A5, CYP3A4, POR, ABCB1, PXR and CYP2C19). A drug interaction with omeprazole was reported and the nephrologist switched to rabeprazole. A lower TAC concentration/dose ratio was achieved, and the patient’s condition improved. In addition, the TTT haplotype of ATP Binding Cassette Subfamily B member 1 (ABCB1) and Pregnane X Receptor (PXR) gene variants seemed to affect TAC pharmacotherapy in the studied patient and could explain the occurrence of long-term adverse effects post-transplantation. These findings suggest that polymorphic variants and co-treatments must be considered in order to achieve the effectiveness of the immunosuppressive therapy with TAC, especially when polymedicated patients are involved. Moreover, pharmacogenetics could influence the drug concentration at the cellular level, both in lymphocyte and in renal tissue, and should be explored in future studies.
Hydration of a multi-layered graphene oxide (GO) paper in water vapor atmosphere was studied by in-situ X-ray scattering over a wide range of relative humidity (RH). The intercalation of water ...molecules physically adsorbed between GO layers induces the expansion of the interlayer distance. Two regimes of adsorption are clearly evidenced according to the variation of the interlayer distance as a function of the relative humidity. The expansion of the interlayer distance is limited to ∼1 Å for RH ranging from 6 to 53%, whereas it is ∼3.5 Å for RH 75–100%. The hydration mechanism corresponds to the progressive adsorption of water molecules onto hydrophilic sites at the surface of GO layers in the low-RH regime, then an additional water monolayer is formed in the high-RH regime.
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The fully aromatic polyamide active layer of a commercial nanofiltration membrane was modified with three generations (G1, G2, and G3) of aramide dendrimers, all with oligoethylene glycol chains on ...their peripheries. Permeation experiments revealed that the rejection of Rhodamine WT, used as a surrogate for organic contaminants, improved 1–2 orders of magnitude for membranes modified with G2 and G3 dendrimers at loadings of 0.7–3.5 μg/cm2 (dendrimer layer thicknesses of ∼1–6 nm) compared to the performance of unmodified membranes. In contrast, the corresponding water permeability of dendrimer-modified membranes decreased by only ∼30%. Although an enhancement in the rejection of H3AsO3, NaCl, and BaCl2 was also observed for dendritic membranes, the effect was less pronounced than that for rhodamine WT. Characterization of membranes modified with 3.5 μg/cm2 dendrimers G2 and G3 by Rutherford backscattering spectrometry with the aid of heavy ion probes (Ag+ and Ba2+) revealed that accessibility of the larger Ba2+ probe to carboxylate groups on the active layer decreased for the membranes modified with dendrimers.
The charge-transfer characteristics of nanostructured carbon/TiO2 electrodes are studied by cyclic voltammetry under photoelectrochemical conditions exploiting the electrooxidation and ...electroreduction of H2O2 in an alkaline medium. Films of composites were prepared by physically mixing TiO2 with 5 wt% of either single-walled carbon nanotubes (SWCNTs) or reduced graphene oxide (rGO). In addition, a layer-by-layer rGO/TiO2 electrode was prepared. Under dark conditions, both mixed SWCNTs and rGO facilitate H2O2 reduction. Under light irradiation, the blank TiO2 electrode shows a cathodic photopotential, the SWCNT/TiO2 an anodic photopotential, and the mixed rGO/TiO2 an increased cathodic photopotential. This scenario unambiguously reveals a photoelectron acceptor behavior for SWCNTs and a photohole acceptor performance for rGO. The latter one also agrees with the photoactivity observed in the layer-by-layer electrode. Overall, the value of H2O2 redox reactions for unraveling the electron-donor or electron-acceptor character of carbon nanostructures in C/metal oxide electrodes is demonstrated.
•H2O2 is a useful probe for the photoelectrochemical assessment of charge transfer phenomena.•Reduced graphene oxide accepts photogenerated holes from TiO2 in alkaline medium.•Single-walled carbon nanotubes accept photogenerated electrons from TiO2 in alkaline medium.
Nanocellulose is increasingly being investigated as a paradigm of a sustainable nanomaterial because of its extraordinary physical and chemical properties, together with its renewable nature and ...worldwide abundance. The rich structural diversity of cellulose materials is represented by different crystalline allomorphs, from which types I and II stand out. While type I is naturally and ubiquitously present, type II is man-made and requires harsh and caustic synthesis conditions such as the so-called mercerization process. Here, we provide an optimal scenario to obtain either type-I or II nanocrystalline cellulose (NCC) by a mercerization-free method consisting only of the acid hydrolysis commonly used to produce nanocellulose from microcellulose. The possibility of having nonmercerized type-II NCC acquires a great relevance since this nanostructure shows particularly appealing properties. Moreover, an entangled and wrapped system arises when used as a dispersing agent for single-walled carbon nanotubes (SWCNTs), significantly different from that of type I. The biological testing of each NCC type and their respective SWCNT–NCC dispersions in human intestinal (Caco-2) cells reveals a general innocuous behavior in both cancer and normal stages of differentiation; however, the type-II-based SWCNT–NCC dispersions display cytotoxicity for cancer cells while enhancing mitochondrial metabolism of normal cells.
Abstract
The formulation of a kinetic Monte Carlo simulation to account for the different possible mechanisms present in the problem of resuspension of aerosol particles is addressed as an extension ...of a former model Benito
et al
(2016
J. Aerosol Sci.
100
26–37). The re-entrainment of micrometer particles to airflow when detached from a surface by aerodynamic forces is modeled using the similitude of the problem with the desorption process from heterogeneous surfaces. Depending on the relative role of the intervening forces, three main mechanisms for movement initiation can be present:
rolling
,
sliding
and
lifting-off
. Three different transition probabilities are defined for each mechanism and the corresponding transition rates calculated for the kinetic process to be simulated. The decisive factor for the development of the model is to set an appropriate dynamical hierarchy to simulate correctly the evolution of the transition rates as the airflow velocity increases, reflecting the stochastic nature of the process, not always fully captured by other Monte Carlo approaches. The model is applied to spherical and elongated particles on a flat surface, reproducing qualitatively well the experimental trends found by other authors for the case of particles with different shapes. It is also demonstrated that, for elongated particles, the main mechanism assisting the detachment is not rolling but sliding, underscoring the need for an adequate choice of the particles shape and detachment mechanism when looking for the critical conditions for particle removal from surfaces.
Resolution of inflammation is orchestrated by specialized proresolving lipid mediators (SPMs), and this would be impaired in some cardiovascular diseases. Among SPMs, resolvins (Rv) have beneficial ...effects in cardiovascular pathologies, but little is known about their effect on cardiovascular damage in hypertension.
Aorta, small mesenteric arteries, heart, and peritoneal macrophages were taken from C57BL/6J mice, infused or not with angiotensin II (AngII; 1.44 mg/kg/day, 14 days) in presence or absence of resolvin D2 (RvD2) (100 ng/mice, every second day) starting 1 day before or 7 days after AngII infusion.
Enzymes and receptors involved in SPMs biosynthesis and signaling were increased in aorta or heart from AngII-infused mice. We also observed a differential regulation of SPMs in heart from these mice. Preventive treatment with RvD2 partially avoided AngII-induced hypertension and protected the heart and large and small vessels against functional and structural alterations induced by AngII. RvD2 increased the availability of vasoprotective factors, modified SPMs profile, decreased cardiovascular fibrosis, and increased the infiltration of pro-resolving macrophages. When administered in hypertensive animals with established cardiovascular damage, RvD2 partially improved cardiovascular function and structure, decreased fibrosis, reduced the infiltration of neutrophils, and shifted macrophage phenotype toward a pro-resolving phenotype.
There is a disbalance between proinflammatory and resolution mediators in hypertension. RvD2 protects cardiovascular function and structure when administered before and after the development of hypertension by modulating vascular factors, fibrosis and inflammation. Activating resolution mechanisms by treatment with RvD2 may represent a novel therapeutic strategy for the treatment of hypertensive cardiovascular disease.
The influence of reduction temperatures on the structure and the sorption capacity of thermally reduced graphene (TRGO) has been investigated systematically. A set of TRGO materials were prepared by ...thermal treatment of parent graphene oxide (GO) at five temperatures (T=200, 300, 500, 700, and 900°C). Investigations of these materials by X-ray diffraction, Raman spectroscopy and X-ray photoemission spectroscopy methods have shown that both the structure and the residual oxygen functional groups on the TRGO surface can be controlled by varying the temperature of the thermal treatment. The data on the sorption and desorption of 4He, H2, N2, Ne and Kr gases in the temperature interval T=2–290K clearly demonstrate that the sorption capacity of TRGO is closely related to the structural changes induced by the treatment temperatures. It is important that the sorption capacities of TRGOs treated at 300°C and at 900°C significantly increase for all the gases used. The prominent increase in the sorption capacity at 300°C is attributed to the structural disorder and liberation of the pores caused by the removal of intercalated water and labile oxygen functional groups (oFGs) favored at this temperature. At 900°C the sorption capacity increases due to the generation of new defects on the TRGO surface, which provide additional access to the internal space between the folds and sheets of the TRGO structure. By tailoring the structural properties we emphasize the potential of TRGO as a highly efficient sorbent.
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