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Cryogels have morphological features that make them interesting for several applications such as catalysis, sensing or tissue engineering. Their interconnected network and open porous structure, build up by primary particles (such as inorganic nanocrystals or polymers), provide these materials with unique physical properties and high specific surface areas. While the library of cryogels is endless, widely used in the polymer chemistry field, in this review we will summarize the structure and properties, applications and challenges of inorganic nanocrystal-based cryogels obtained by freezing and freeze-drying an aqueous nanoparticle colloid. This fast, easy and versatile gelation method will be outlined, along with the corresponding macro-, micro- and nano-structures and gel morphologies that can be obtained, for example, by changing the freezing temperature or by using one nanoparticle system or nanoparticle mixtures. Their applications towards electrocatalysis, photocatalysis and photoelectrochemical sensing will be highlighted, as well as the challenges and prospects of these materials.

© 2023 by the authors. Licensee MDPI This research was funded by the Tunisian Ministry of Higher Education and Scientific Research and by the Ministerio de Ciencia e Innovación (MCINN), grant number PID2021-123112OBC21., We have investigated the structural, magnetic, and electrical transport properties of Pr_(0.7)Sr_(0.3)Mn_(1-x)Co_(x) O_(3) nanopowders (x = 0, 0.05, 0.10 and 0.15). The Pechini Sol-gel method was used to synthesize these nanopowders. X-ray diffraction at room temperature shows that all the nano powders have an orthorhombic structure of Pnma space group crystallography. The average crystallite size of samples x = 0, 0.05, 0.10, and 0.15 are 33.78 nm, 29 nm, 33.61 nm, and 24.27 nm, respectively. Semi-quantitative chemical analysis by energy dispersive spectroscopy (EDS) confirms the expected stoichiometry of the sample. Magnetic measurements indicate that all samples show a ferromagnetic (FM) to paramagnetic (PM) transition with increasing temperature. The Curie temperature T-C gradually decreases (300 K, 270 K, 250 K, and 235 K for x = 0, 0.05, 0.10, and 0.15, respectively) with increasing Co concentrations. The M-H curves for all compounds reveal the PM behavior at 300 K, while the FM behavior characterizes the magnetic hysteresis at low temperature (5 K). The electrical resistivity measurements show that all compounds exhibit metallic behavior at low temperature (T < T rho) well fitted by the relation rho = rho_(0) + rho_(2)T^(2) + rho_(4.5) T^(4.5) and semiconductor behavior above T rho (T > T rho), for which the electronic transport can be explained by the variable range hopping model and the adiabatic small polaron hopping model. All samples have significant magnetoresistance (MR) values, even at room temperature. This presented research provides an innovative and practical approach to develop materials in several technological areas, such as ultra-high density magnetic recording and magneto resistive sensors., Ministerio de Ciencia e Innovación (MICINN), Tunisian Ministry of Higher Education and Scientific Research, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

©2016 American Physical Society. We thank Prof. L. Pezzé for helpful comments. We acknowledge financial support from Spanish Ministerio de Economía y Competitividad Projects No. FIS2012-33152 and No. FIS2012-35583, and from the Comunidad Autónoma de Madrid research consortium QUITEMAD+ Grant No. S2013/ICE-2801., We examine the performance of a nonlinear fiber gyroscope for improved signal detection beating the quantum limits of its linear counterparts. The performance is examined when the nonlinear gyroscope is illuminated by practical field states, such as coherent and quadrature squeezed states. This is compared with the case of more ideal probes such as photon-number states., Ministerio de Economía y Competitividad (MINECO), Comunidad de Madrid, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

Copyright: © 2023 by the authors. This research was supported by the Ministry of Higher Education and Scientific Research (Tunisia) and funded by Ministerio de Economia y Competitividad (MINECO) grant number PID2021-123112OB-C21., The present study aims at the integration of the "oxalic conversion" route into "green chemistry" for the synthesis of copper oxide nanoparticles (CuO-NPs) with controllable structural, morphological, and magnetic properties. Two oxalate-containing precursors (H_2C_2º_4.2H_2O and (NH_4)_(2)C_2O_4.H_2O) and different volume ratios of a mixed water/glycerol solvent were tested. First, the copper oxalates were synthesized and then subjected to thermal decomposition in air at 400 degrees C to produce the CuO powders. The purity of the samples was confirmed by X-ray powder diffraction (XRPD), and the crystallite sizes were calculated using the Scherrer method. The transmission electron microscopy (TEM) images revealed oval-shaped CuO-NPs, and the scanning electron microscopy (SEM) showed that morphological features of copper oxalate precursors and their corresponding oxides were affected by the glycerol (V/V) ratio as well as the type of C_2º_4^2- starting material. The magnetic properties of CuO-NPs were determined by measuring the temperature-dependent magnetization and the hysteresis curves at 5 and 300 K. The obtained results indicate the simultaneous coexistence of dominant antiferromagnetic and weak ferromagnetic behavior., Ministerio de Ciencia e Innovación (MICINN), Ministry of Higher Education and Scientific Research (Tunisia), Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

Assemblies of colloidal nanoparticles (NPs) into various functional superstructures, such as ordered or nonordered, microscopic or macroscopic, and templated or self-supported, have recently attracted a lot of research interest. The continuous development of colloidal nanoparticle synthesis enables a fine-tuning of the structure and properties of such functional superstructures leading to numerous new applications. Herein, it is aimed to summarize a variety of assemblies based on ordered self-assembled NPs, e.g., stacked nanoplatelets, and nonordered self-assembled NPs, e.g., nanoparticle-based aerogels and cryoaerogels, systems ranging from the microscopic to the macroscopic range. Depending on the materials of the nanoparticle building blocks used, e.g., metallic, magnetic, semiconducting, or their combination in hybrid systems, both ordered and nonordered assemblies yield interesting properties for a wide variety of applications, such as catalysis, photocatalysis, or sensing, which are highlighted and discussed.

Several studies suggest that single-domain biogenic magnetic nanoparticles could play a major role on the effectiveness of oscillating magnetic fields (OMFs) in improving food freezing. To evaluate the potential role of superparamagnetic biogenic particles, we performed freezing experiments in a colloidal dispersion of <10-nm maghemite nanoparticles (MNPs) subjected or not to a 31.3-mT OMF at 50 Hz. Our results show that, at our experimental conditions, Néel mechanism governs the alignment of magnetic dipole moments and, therefore, no significant MNPs rotation, able to disturb the ordering of water molecules, should be expected during OMF experiments. Accordingly, no effects of the applied OMF were observed either on supercooling, ice nucleation, or on freezing kinetics even though heat removal was slightly increased during the precooling step. These results suggest that weak OMFs usually applied in commercial freezers should not produce any significant effect on superparamagnetic nanoparticles present in food that could improve the freezing process.

The present study aims at the integration of the “oxalic conversion” route into “green chemistry” for the synthesis of copper oxide nanoparticles (CuO-NPs) with controllable structural, morphological, and magnetic properties. Two oxalate-containing precursors (H2C2O4.2H2O and (NH4)2C2O4.H2O) and different volume ratios of a mixed water/glycerol solvent were tested. First, the copper oxalates were synthesized and then subjected to thermal decomposition in air at 400 °C to produce the CuO powders. The purity of the samples was confirmed by X-ray powder diffraction (XRPD), and the crystallite sizes were calculated using the Scherrer method. The transmission electron microscopy (TEM) images revealed oval-shaped CuO-NPs, and the scanning electron microscopy (SEM) showed that morphological features of copper oxalate precursors and their corresponding oxides were affected by the glycerol (V/V) ratio as well as the type of C2O42− starting material. The magnetic properties of CuO-NPs were determined by measuring the temperature-dependent magnetization and the hysteresis curves at 5 and 300 K. The obtained results indicate the simultaneous coexistence of dominant antiferromagnetic and weak ferromagnetic behavior.

MOGHE is defined as mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy. Approximately half of the patients with histopathologically confirmed MOGHE carry a brain somatic variant in the SLC35A2 gene encoding a UDP-galactose transporter. Previous research showed that D-galactose supplementation results in clinical improvement in patients with a congenital disorder of glycosylation due to germline variants in SLC35A2. We aimed to evaluate the effects of D-galactose supplementation in patients with histopathologically confirmed MOGHE, with uncontrolled seizures or cognitive impairment and epileptiform activity at the EEG after epilepsy surgery (NCT04833322). Patients were orally supplemented with D-galactose for 6 months in doses up to 1.5 g/kg/day and monitored for seizure frequency including 24-h video-EEG recording, cognition and behavioral scores, i.e., WISC, BRIEF-2, SNAP-IV, and SCQ, and quality of life measures, before and 6 months after treatment. Global response was defined by > 50% improvement of seizure frequency and/or cognition and behavior (clinical global impression of “much improved” or better). Twelve patients (aged 5–28 years) were included from three different centers. Neurosurgical tissue samples were available in all patients and revealed a brain somatic variant in SLC35A2 in six patients (non-present in the blood). After 6 months of supplementation, D-galactose was well tolerated with just two patients presenting abdominal discomfort, solved after dose spacing or reduction. There was a 50% reduction or higher of seizure frequency in 3/6 patients, with an improvement at EEG in 2/5 patients. One patient became seizure-free. An improvement of cognitive/behavioral features encompassing impulsivity (mean SNAP-IV − 3.19 [− 0.84; − 5.6]), social communication (mean SCQ − 2.08 [− 0.63; − 4.90]), and executive function (BRIEF-2 inhibit − 5.2 [− 1.23; − 9.2]) was observed. Global responder rate was 9/12 (6/6 in SLC35A2-po