Expanding the DNA-encoded library toolbox: identifying small molecules targeting RNA.

DNA-encoded library (DEL) technology is a powerful tool for small molecule identification in drug discovery, yet the reported DEL selection strategies were applied primarily on protein targets in either purified form or in cellular context. To expand the application of this technology, we employed DEL selection on an RNA target HIV-1 TAR (trans-acting responsive region), but found that the majority of signals were resulted from false positive DNA-RNA binding. We thus developed an optimized selection strategy utilizing RNA patches and competitive elution to minimize unwanted DNA binding, followed by k-mer analysis and motif search to differentiate false positive signal. This optimized strategy resulted in a very clean background in a DEL selection against Escherichia coli FMN Riboswitch, and the enriched compounds were determined with double digit nanomolar binding affinity, as well as similar potency in functional FMN competition assay. These results demonstrated the feasibility of small molecule identification against RNA targets using DEL selection. The developed experimental and computational strategy provided a promising opportunity for RNA ligand screening and expanded the application of DEL selection to a much wider context in drug discovery.

Increasing Prevalence of Nontuberculous Mycobacteria in Respiratory Specimens from US-Affiliated Pacific Island Jurisdictions1.

Nontuberculous mycobacteria (NTM) respiratory infections represent a growing public health problem in many countries. However, there are limited published epidemiologic studies for the Western Pacific region. We reviewed respiratory specimens submitted to Diagnostic Laboratory Services in Hawaii, USA, for culture of Mycobacterium tuberculosis during August 2007-December 2011 to determine the NTM isolation rate. We observed a statistically significant increase in the rate of specimens with NTM isolated in respiratory culture (adjusted rate ratio per year 1.65, 95% CI 1.54-1.77; p<0.01). In contrast, the number of patients with respiratory cultures positive for M. tuberculosis showed no increase (adjusted rate ratio per year 0.98, 95% CI 0.94-1.01; p = 0.19). A 6-month subset of NTM isolates was identified by using a nucleic acid probe or 16S rRNA sequencing. M. avium complex and M. fortuitum were the most common NTM identified.

Replication of a genome-wide association study on essential hypertension in Mongolians.

Replication of genome-wide significant association SNPs in independent populations is an essential approach for identifying gene-disease relationships. Therefore, we sought to investigate the top 21 SNPs (rs10507454, rs11897156, rs11897991, rs12325203, rs12541835, rs13395322, rs1525035, rs16936892, rs17010027, rs17045859, rs17136827, rs1866525, rs2045590, rs4547758, rs4655688, rs7107438, rs761353, rs8127139, rs9312305, rs9407874 and rs9865108) from a genome-wide association study of essential hypertension in Mongolians. This was a community-based case-control study involving 428 hypertensives and 638 normotensives from Kerqinzuoyihou Banner,Tongliao, Inner Mongolian Autonomous Region, China. Genotyping was conducted with Sequenom MassArray (®) SNP detection technology. Overall, there were no significant differences in the genotype distributions and allele frequencies between the cases and controls. There was a significant difference between the allele frequencies at locus rs17010027 in cases (high systolic blood pressure) and controls in female (p = .036). There were significant differences in the distribution of genotypes and the allele frequencies at locus rs10507454 between cases (high diastolic blood pressure) and controls (p = .019 and p = .022, respectively) especially in male (p = .009 and p = .011, respectively). rs17010027 is associated with high systolic blood pressure in female, and rs10507454 is associated with high diastolic blood pressure especially in male of this Mongolian population.

Combining anti-IgE with oral immunotherapy.

Food allergy is a significant medical problem that affects up to 8% of children in developed countries. At present, there are no curative therapies available in routine practice and management of food allergy involves strict allergen avoidance, education, and prompt treatment upon accidental exposure. Oral immunotherapy (OIT) is an efficacious experimental approach to food allergy and has been shown to provide a substantial benefit in terms of allergen desensitization. However, OIT is associated with high rates of allergic reactions, and the period of protection offered by OIT appears to be limited and highly variable. Recurrence of allergen sensitivity after a period of treatment discontinuation is commonly observed. With the aim of overcoming these limitations of OIT, several trials have studied omalizumab (anti-IgE monoclonal antibody) as an adjuvant treatment for patients undergoing OIT. Results from these trials have shown that the addition of omalizumab to OIT leads to a significant decrease in the frequency and severity of reactions, which allows for an increase in the threshold of tolerance to food allergens. This review provides a summary of the current literature and addresses some of the key questions that remain regarding the use of omalizumab in conjunction with OIT.

Structural, Magnetic, and Electronic Properties of Mixed Spinel NiFe2-xCrxO4 Nanoparticles Synthesized by Chemical Combustion.

A series of nickel-chromium-ferrite NiFe2-xCrxO4 (with x = 1.25) nanoparticles (NPs) with a cubic spinel structure and with size d ranging from 1.6 to 47.7 nm was synthesized by the solution combustion method. A dual structure of all phonon modes revealed in Raman spectra is associated with metal cations of different types present in the spinel lattice sites. Mössbauer spectra of small NPs exhibit superparamagnetic behavior. However, the transition into the paramagnetic state occurs at a temperature that is unusually high for small particles (TN is about 240 K in the d = 4.5 nm NPs). The larger NPs with d > 20 nm do not exhibit superparamagnetic properties up to the Neel temperature. From the magnetic and Mössbauer data, the cation occupation of the tetrahedral (A) and octahedral [B] sites was determined (Fe0.75Ni0.25)[Ni0.75Cr1.25]O4. The saturation magnetization MS in the largest NPs is about (0.98-0.95) µB, which is more than twice higher the value in bulk ferrite (Fe)[CrNi]O4. At low temperatures the total magnetic moment of the ferrite coincides with the direction of the B-sublattice moment. In the NPs with d > 20 nm, the compensation of the magnetic moments of A- and B-sublattices was revealed at about Tcom = 360-365 K. This value significantly exceeds the point Tcom in bulk ferrites NiFexCr2-xO4 (about 315 K) with the similar Cr concentration. However, in the smaller NPs NiFe0.75Cr1.25O4 with d ≤ 11.7 nm, the compensation effect does not occur. The magnetic anomalies are explained in terms of highly frustrated magnetic ordering in the B sublattice, which appears due to the competition of AFM and FM exchange interactions and results in a canted magnetic structure.

Structural, magnetic and electronic properties of Fe1+xGa2-xO4 nanoparticles synthesized by the combustion method.

The combustion method was used to prepare a precursor powder of an iron-gallium oxide compound which was further heat-treated in order to obtain a set of Fe1+xGa2-xO4 nanoparticles. All samples have a cubic spinel-type structure (space group Fd3[combining macron]m) and the particle size varies from 1.8 to 28.0 nm depending on the treatment conditions. From the comparative analysis by XRD, EDS, and Raman and Mössbauer spectroscopy the creation of a new spinel phase γ-FeGaO3, which was mainly located on the particle surface, was established. As a result, the composition consists of a FeGa2O4 core covered by a FeGaO3 shell. The relative content of FeGa2O4/FeGaO3 compounds in the composites can be varied by heat treatment. The maximum in the ZFC magnetization curves appeared in all samples at about 20-30 K corresponding to the spin-freezing temperature Tsg, which is much higher than in the bulk compound with a pure inverse spinel structure (Ga)[FeGa]O4. The values of effective Curie temperature ΘC for the Fe1+xGa2-xO4 nanoparticles are rather high and positive, indicating a ferromagnetic interaction between iron ions. The high values of the magnetic frustration parameter f = ΘC/Tsg (up to 7) indicate a high degree of magnetic frustration. The low temperature Mössbauer data reveal the magnetic ordering of Fe ions in all samples with the magnetic transition at about 20-26 K depending on the particle size. The specific features of the Mössbauer parameters indicate the properties of non-homogeneous magnetic systems with frustrated interactions specific to spin-glasses. The magnetic system behaves as a spin-glass below Tsg and it is superparamagnetic above Tsg. Such a system is called a "super-spin-glass". The anisotropy energy Eanis strongly depends on the content of Fe(2+) and Fe(3+) ions which contribute to the magnetocrystalline Ecryst and exchange Eex anisotropies, respectively. The anisotropy energy can be tuned by variation of the content of the (FeGaO3)-(FeGa2O4) phases in these complex composites.

Novel N-Substituted 2-(2-(Adamantan-1-yl)-1H-Indol-3-yl)-2-Oxoacetamide Derivatives: Synthesis and Biological Evaluation.

In this study, a series of novel N-substituted 2-(2-(adamantan-1-yl)-1H-indol-3-yl)-2-oxoacetamide derivatives were synthesized, and evaluated for their cytotoxicity in human cell lines including Hela (cervical cancer), MCF7 (breast cancer ) and HepG2 (liver cancer). Several compounds were found to have potent anti-proliferative activity against those human cancer cell lines and compound 5r showed the most potent biological activity against HepG2 cells with an IC50 value of 10.56 ± 1.14 µΜ. In addition, bioassays showed that compound 5r induced time-dependent and dose-dependent cleavage of poly ADP-ribose polymerase (PARP), and also induced a dose-dependent increase in caspase-3 and caspase-8 activity, but had little effect on caspase-9 protease activity in HepG2 cells. These results provide evidence that 5r-induced apoptosis in HepG2 cell is caspase-8-dependent.

Synthesis and magnetic properties of the chromium-doped iron sulfide Fe1-xCrxS single crystalline nanoplates with a NiAs crystal structure.

Single crystalline iron sulfide nanoparticles doped with chromium Fe1-xCrxS (0 ≤x≤ 0.15) have been successfully prepared by a thermal decomposition method. The particles are self-organized into the single crystalline plates with the accurate hexagonal shape and dimensions up to 1 µ in plane and about 30-40 nm in thickness. The samples have the NiAs-type crystal structure (P63/mmc) at all Cr concentrations up to x = 0.15. Fe(57)-Mössbauer spectroscopy data reveal four nonequivalent iron sites in these nanocrystals related to the different number of cation vacancies in neighboring of the iron atoms. A 2C-type superstructure or a mixture of 2C and 3C superstructures of vacancy ordering can appear in these samples. It was established that in the Fe1-xCrxS series chromium prefers to replace iron in the cation layers containing vacancies at 0.00 < x < 0.10 and Cr atoms occupy both iron and vacant sites at x > 0.10. The specific magnetic properties, which can be tuned by chromium doping, enable potential applications of these nanoparticles in technical devices using the material with thermally activated magnetic memory, for example, switches or storages.

Structural, magnetic, and electronic properties of iron selenide Fe6-7Se8 nanoparticles obtained by thermal decomposition in high-temperature organic solvents.

Iron selenide nanoparticles with the NiAs-like crystal structure were synthesized by thermal decomposition of iron chloride and selenium powder in a high-temperature organic solvent. Depending on the time of the compound processing at 340 °C, the nanocrystals with monoclinic (M)-Fe3Se4 or hexagonal (H)-Fe7Se8 structures as well as a mixture of these two phases can be obtained. The magnetic behavior of the monoclinic and hexagonal phases is very different. The applied-field and temperature dependences of magnetization reveal a complicated transformation between ferrimagnetic (FRM) and antiferromagnetic (AFM) structures, which can be related to the spin rotation process connected with the redistribution of cation vacancies. From XRD and Mössbauer data, the 3c type superstructure of vacancy ordering was found in the hexagonal Fe7Se8. Redistribution of vacancies in Fe7Se8 from random to ordered leads to the transformation of the magnetic structure from FRM to AFM. The Mössbauer data indicate that vacancies in the monoclinic Fe3Se4 prefer to appear near the Fe(3+) ions and stimulate the magnetic transition with the rotation of the Fe(3+) magnetic moments. Unusually high coercive force Hc was found in both (H) and (M) nanocrystals with the highest ("giant") value of about 25 kOe in monoclinic Fe3Se4. This is explained by the strong surface magnetic anisotropy which is essentially larger than the core anisotropy. Such a large coercivity is rare for materials without rare earth or noble metal elements, and the Fe3Se4-based compounds can be the low-cost, nontoxic alternative materials for advanced magnets. In addition, an unusual effect of "switching" of magnetization in a field of 10 kOe was found in the Fe3Se4 nanoparticles below 280 K, which can be important for applications.

Comparing conventional treatment, single-target rTMS, or dual-target rTMS for the treatment of post-stroke cognitive impairment - clinical effects and neuroscientific insights: study protocol for a randomized controlled trial.

BACKGROUND: Although increasing evidence suggests that repetitive transcranial magnetic stimulation may help improve cognitive impairment after stroke, its clinical efficacy is still limited. This limitation may be due to the fact that the left dorsolateral prefrontal cortex (DLPFC) is only one of several brain areas involved in post-stroke cognitive impairment (PSCI). The aim of the present study is to reveal whether dual-target stimulation is superior to single-target stimulation and usual care in the treatment of PSCI. METHODS: A single-center, single-blind, randomized controlled trial will be conducted, and fifty-seven PSCI patients will be recruited and randomly assigned to one of three groups based on the stimulating site. The primary outcome is cognitive function, measured using the Montreal Cognitive Assessment Beijing Version (MoCA-BJ) and Mini-Mental Status Examination (MMSE). The secondary outcomes are the modified Barthel Index (MBI), Trail-Making Test (TMT), and digital span test (DST). Furthermore, changes in brain activity are assessed using transcranial Doppler sonography (TCD) examination and serum levels of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) closely related to nerve and vascular repair after brain injury. All outcomes will be measured at baseline and 4 weeks after treatment. DISCUSSION: If dual-target rTMS in significant improvements in cognitive function, this method could be considered as a first-line clinical treatment for PSCI. This proposed study has the potential to identify a new, evidence-based intervention that can enhance cognition and independent living in patients with cognitive impairment after stroke. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2200066184 . It was registered on 26 November 2022.

Facile Synthesis of Chromium-Doped Fe1.1Mn1.9O4 Nanoparticles and the Effect of Cr Content on Their Magnetic and Structural Properties.

In the present study, Fe1.1(CrxMn1-x)1.9O4 nanoparticles (0 ≤ x ≤ 0.5) were successfully synthesized by a combustion method, and the influence of Cr substitution on the structural and magnetic properties of the obtained nanoparticles was studied by various methods. The structural analysis revealed that the sample with x = 0 has a tetragonal structure, while all Cr-doped samples crystallize into a cubic structure. Additionally, the results of TEM show that doping with chromium leads to an increase in particle size. The magnetic hysteresis loops demonstrate the behavior typical for soft magnetic materials with low coercivity and remanence magnetization. The magnetic measurements revealed that the saturation magnetization of the obtained nanoparticles demonstrates a decreasing trend with increasing Cr content. The influence of chromium doping on the observation change in saturation magnetization is discussed. Based on the results of temperature-dependent magnetization measurements, it was found that the temperature of a magnetic transition in synthesized nanoparticles depends on Cr content.

Temperature-Induced Irreversible Structural Transition in Fe1.1Mn1.9O4 Nanoparticles Synthesized by Combustion Method.

Fe1.1Mn1.9O4 nanoparticles were successfully synthesized using a combustion method. The influence of the heating temperature on the evolution of the structural and magnetic properties has been studied using various methods. The structural analysis results revealed that as-synthesized nanoparticles have a tetragonal structure with an average size of ~24 nm. The magnetic measurements of the sample showed its ferrimagnetic nature at room temperature with hysteresis at low fields. Temperature-dependent magnetization measurements allowed for the conclusion that the Curie temperature for Fe1.1Mn1.9O4 nanoparticles was ~465 °C. After high-temperature magnetic measurements, during which the samples were heated to various maximum heating temperatures (Tmax.heat.) in the range from 500 to 900 °C, it was found that the structure of the samples after cooling to room temperature depended on the heating temperature. Herewith, when the heating temperature was 600 < Tmax.heat. < 700 °C, an irreversible structural phase transition occurred, and the cooled samples retained a high-temperature cubic structure. The results of the magnetic analysis showed that the samples, following high-temperature magnetic measurements, demonstrated ferrimagnetic behavior.

Size-Dependent Magnetic and Magneto-Optical Properties of Bi-Doped Yttrium Iron Garnet Nanopowders.

Bi-doped yttrium iron garnet nanopowders were successfully synthesized by a combustion method at different synthesis conditions, and the evolution of their structural, magnetic, and magneto-optical properties has been studied by various methods. X-ray diffraction analysis revealed that crystallite size increases with increase as in annealing time (tA) well as in annealing temperature (TA) and varied from 15.2 nm (TA = 650 °C, tA = 0.5 h) to 44.5 nm (TA = 800 °C, tA = 12 h). The magnetic hysteresis loops exhibit behavior characteristic of soft magnetic materials; herewith, the saturation magnetization demonstrates a growing trend with increasing crystallite size (D). The behavior of the coercivity indicates that, at room temperature, the transition between single-domain and multidomain states occurs at D = 35.3 nm. It was found that the size effect in the MCD spectra is clearly observed for the samples with crystallite sizes less than 42.2 nm for an intersublattice charge-transfer transition and a crystal-field tetrahedral transition. The influence of cation redistribution on the observed changes has been discussed.

Carbon Double Coated Fe3O4@C@C Nanoparticles: Morphology Features, Magnetic Properties, Dye Adsorption.

This work is devoted to the study of magnetic Fe3O4 nanoparticles doubly coated with carbon. First, Fe3O4@C nanoparticles were synthesized by thermal decomposition. Then these synthesized nanoparticles, 20-30 nm in size were processed in a solution of glucose at 200 °C during 12 h, which led to an unexpected phenomenon-the nanoparticles self-assembled into large conglomerates of a regular shape of about 300 nm in size. The morphology and features of the magnetic properties of the obtained hybrid nanoparticles were characterized by transmission electron microscopy, differential thermo-gravimetric analysis, vibrating sample magnetometer, magnetic circular dichroism and Mössbauer spectroscopy. It was shown that the magnetic core of Fe3O4@C nanoparticles was nano-crystalline, corresponding to the Fe3O4 phase. The Fe3O4@C@C nanoparticles presumably contain Fe3O4 phase (80%) with admixture of maghemite (20%), the thickness of the carbon shell in the first case was of about 2-4 nm. The formation of very large nanoparticle conglomerates with a linear size up to 300 nm and of the same regular shape is a remarkable peculiarity of the Fe3O4@C@C nanoparticles. Adsorption of organic dyes from water by the studied nanoparticles was also studied. The best candidates for the removal of dyes were Fe3O4@C@C nanoparticles. The kinetic data showed that the adsorption processes were associated with the pseudo-second order mechanism for cationic dye methylene blue (MB) and anionic dye Congo red (CR). The equilibrium data were more consistent with the Langmuir isotherm and were perfectly described by the Langmuir-Freundlich model.

Core-Shell Fe3O4@C Nanoparticles for the Organic Dye Adsorption and Targeted Magneto-Mechanical Destruction of Ehrlich Ascites Carcinoma Cells.

The morphology, structure, and magnetic properties of Fe3O4 and Fe3O4@C nanoparticles, as well their effectiveness for organic dye adsorption and targeted destruction of carcinoma cells, were studied. The nanoparticles exhibited a high magnetic saturation value (79.4 and 63.8 emu/g, correspondingly) to facilitate magnetic separation. It has been shown that surface properties play a key role in the adsorption process. Both types of organic dyes-cationic (Rhodomine C) and anionic (Congo Red and Eosine)-were well adsorbed by the Fe3O4 nanoparticles' surface, and the adsorption process was described by the polymolecular adsorption model with a maximum adsorption capacity of 58, 22, and 14 mg/g for Congo Red, Eosine, and Rhodomine C, correspondingly. In this case, the kinetic data were described well by the pseudo-first-order model. Carbon-coated particles selectively adsorbed only cationic dyes, and the adsorption process for Methylene Blue was described by the Freundlich model, with a maximum adsorption capacity of 14 mg/g. For the case of Rhodomine C, the adsorption isotherm has a polymolecular character with a maximum adsorption capacity of 34 mg/g. To realize the targeted destruction of the carcinoma cells, the Fe3O4@C nanoparticles were functionalized with aptamers, and an experiment on the Ehrlich ascetic carcinoma cells' destruction was carried out successively using a low-frequency alternating magnetic field. The number of cells destroyed as a result of their interaction with Fe3O4@C nanoparticles in an alternating magnetic field was 27%, compared with the number of naturally dead control cells of 6%.

Preparation and Magnetic Properties of Cobalt-Doped FeMn2O4 Spinel Nanoparticles.

Mixed-metal oxide nanoparticles have attracted great scientific interest since they find applications in many fields. However, the synthesis of size-controlled and composition-tuned mixed-metal oxide nanoparticles is a great challenge that complicates their study for practical application. In this study, Co-doped FeMn2O4 nanoparticles were synthesized by the solvothermal method in which the crystallization was carried out under autogenous pressure at temperatures of 190 °C for 24 h. The influence of Co doping on the evolution of the structural and magnetic properties was investigated by various methods. It was found from XRD data that crystallite size decreases from 9.1 to 4.4 nm with the increase in Co content, which is in good agreement with the results of TEM. Based on the results of magnetic measurements, it was found that the saturation magnetization first increases with an increase in the cobalt content and reaches its maximum value at x = 0.4, and a further increase in x leads to a decrease in the saturation magnetization. The influence of cation redistribution on the observed changes has been discussed.

Synthesis of Fe1-xS Nanoparticles with Various Superstructures by a Simple Thermal Decomposition Route and Their Magnetic Properties.

Pyrrhotite nanoparticles with 5C and 3C superstructures were synthesized via a simple one-step thermal decomposition method in which hexadecylamine was used as a solvent at various reaction temperatures (TR). Structural analysis showed that at TR = 360 °C, almost uniform in size and shape Fe7S8 nanoparticles with 3C superstructure are formed, and an increase in the reaction temperature leads to the formation of Fe9S10 nanoparticles (5C superstructure), herewith a significant increase in the size of nanoparticles is observed. High-temperature magnetic measurements in 5 repeated heating-cooling cycles revealed that after the first heating branch in the Fe9S10 samples, the λ-Peak transition disappears, and the magnetization has a Weiss-type behavior characteristic of the Fe7S8 sample. The change in the behavior of magnetization can be explained by the redistribution of iron vacancies, which changes the initial phase composition of nanoparticles.

USP7, negatively regulated by miR-409-5p, aggravates hypoxia-induced cardiomyocyte injury.

Hypoxia-induced apoptosis is linked to the pathogenesis of myocardial infarction (MI) and heart failure. Ubiquitin-specific peptidase 7 (USP7) is related to catabolic/pro-apoptotic signaling. However, its role in cardiomyocyte injury is unclear. In this study, we aimed to investigate the role and the underlying regulatory mechanism of USP7 in MI. H9c2 cardiomyocytes were cultured in hypoxia to establish an in vitro model of myocardial hypoxic/ischemic injury. Sprague-Dawley (SD) rats were used to establish animal models with MI. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot assays were performed to evaluate the expression levels of miR-409-5p, USP7, and p53, respectively. After USP7 and miR-409-5p were selectively regulated in H9c2 cells, the inflammatory response, apoptosis, and cell viability were detected by ELISA, flow cytometry, and MTT assay, respectively. The interaction between USP7 and miR-409-5p was determined by bioinformatics analysis, qRT-PCR, Western blot, and dual-luciferase reporter assay. LVEF, LVIDd, and LVIDs of rats after MI were also measured. USP7 expression was markedly elevated while miR-409-5p expression was significantly down-regulated in H9c2 cells under hypoxic culture. Augmentation of USP7 expression led to a dramatic promotion of hypoxia-induced apoptosis of cardiomyocytes, accompanied by an increase in the secretion of the cytokines IL-1ß, TNF-α, and IL-6. Myocardial injury markers LDH, cTnI, and CK-MB expressions were also increased. Besides, overexpression of USP7 aggravated left ventricular remodeling and decreased left ventricular function of the rats. Conversely, the up-regulation of miR-409-5p expression protected H9c2 cells from apoptosis and inhibited the release of cytokines and myocardial injury. Left ventricular remodeling and left ventricular function were also improved by miR-409-5p overexpression. Furthermore, USP7 was identified as a target of miR-409-5p and the overexpression of miR-409-5p reversed the effects of USP7 on H9c2 cells. USP7 exacerbates myocardial ischemic injury by promoting inflammation and apoptosis of cardiomyocytes, and the up-regulation of its expression is partly caused by the down-regulation of miR-409-5p expression.

Amino-Functionalized Fe3O4@SiO2 Core-Shell Magnetic Nanoparticles for Dye Adsorption.

Fe3O4@SiO2 core-shell nanoparticles (NPs) were synthesized with the co-precipitation method and functionalized with NH2 amino-groups. The nanoparticles were characterized by X-ray, FT-IR spectroscopy, transmission electron microscopy, selected area electron diffraction, and vibrating sample magnetometry. The magnetic core of all the nanoparticles was shown to be nanocrystalline with the crystal parameters corresponding only to the Fe3O4 phase covered with a homogeneous amorphous silica (SiO2) shell of about 6 nm in thickness. The FT-IR spectra confirmed the appearance of chemical bonds at amino functionalization. The magnetic measurements revealed unusually high saturation magnetization of the initial Fe3O4 nanoparticles, which was presumably associated with the deviations in the Fe ion distribution between the tetrahedral and octahedral positions in the nanocrystals as compared to the bulk stoichiometric magnetite. The fluorescent spectrum of eosin Y-doped NPs dispersed in water solution was obtained and a red shift and line broadening (in comparison with the dye molecules being free in water) were revealed and explained. Most attention was paid to the adsorption properties of the nanoparticles with respect to three dyes: methylene blue, Congo red, and eosin Y. The kinetic data showed that the adsorption processes were associated with the pseudo-second order mechanism for all three dyes. The equilibrium data were more compatible with the Langmuir isotherm and the maximum adsorption capacity was reached for Congo red.

Synthesis, characterization and magnetic properties of nearly monodisperse CuCr2Se4 nanoparticles.

Nearly monodisperse CuCr(2)Se(4) hexagon-shaped nanoparticles with crystallite sizes from 15.1 to 24.3 nm were synthesized by thermal decomposition of metal chlorides and selenium powder in oleylamine. In addition, the 'flower'-shaped CuCr(2)Se(4) nanoparticles with a crystallite size 19.8 nm were also fabricated under similar conditions using heptanoic acid. Magnetic measurements show that all samples reveal ferromagnetic behavior below 350 K. The 'flower'-shaped nanoparticles have saturation magnetization, coercivity and remanent magnetization higher than the hexagon-shaped nanoparticles. However, the Curie temperature of the 'flower'-shaped nanoparticles (approximately 380 K) is somewhat lower than in the hexagon-shaped nanoparticles (420-430 K). These phenomena may be associated with the shape and surface anisotropy which would exert a tremendous influence on the particle's magnetic properties.