Nm In Size Research Articles

Microstructure refinement and wear resistance enhancement of cost-effective Fe50−2xMn30Co10Cr10NixCux (x = 0, 5 at%) high-entropy alloys through cyclic closed-die forging process

Novel low-cost Fe50−2xMn30Co10Cr10NixCux (x = 0, 5 at%) high-entropy alloys (HEAs) were produced by vacuum melting and then processed by the cyclic closed-die forging (CCDF) process. It was found that both the as-homogenized and CCDF-processed specimens primarily consisted of a single face-centered cubic (FCC) structure, and the severe plastic strain through CCDF did not result in phase transformations. The microstructure of the CCDF-processed Fe50Mn30Co10Cr10 alloy after the sixth pass demonstrated a uniform structure with ultrafine grains measuring 285 nm in size, whereas for the CCDF-processed Fe40Mn30Co10Cr10Ni5Cu5 alloy, the grain size was 135 nm, with a relatively uniform distribution. The CCDF-processed Fe50Mn30Co10Cr10 and especially the Fe40Mn30Co10Cr10Ni5Cu5 alloy exhibited significantly higher microhardness compared to the as-homogenized state, with microhardness values being 2.42 and 2.72 times higher, respectively. Furthermore, the wear test results indicated that the CCDF processing effectively increased the wear resistance of the alloys, which was attributed to the changes in morphology and distribution of as-cast dendrites, along with the grain refinement of the matrix phase during CCDF. The CCDF-processed Fe40Mn30Co10Cr10Ni5Cu5 alloy exhibited the lowest wear rate, i.e., (1.2 ± 0.2) × 10–5 mm3.N−1.m−1, whereas that for the Fe50Mn30Co10Cr10 alloy was (2.4 ± 0.1) × 10–5 mm3.N−1.m−1. Analysis of wear surfaces indicated that the wear mechanisms of the as-homogenized HEAs were adhesive wear and abrasive wear with some delamination, while plastic deformation and adhesive wear were significantly reduced in the CCDF-processed specimens, especially in the Fe40Mn30Co10Cr10Ni5Cu5 alloy. These findings suggest that CCDF has the potential to achieve cost-effective nanostructured HEAs and to implement them in engineering applications.

Influenza A Vaccine Candidates Based on Virus-like Particles Formed by Coat Proteins of Single-Stranded RNA Phages Beihai32 and PQ465.

Efficient control of influenza A infection can potentially be achieved through the development of broad-spectrum recombinant vaccines based on conserved antigens. The extracellular domain of the transmembrane protein M2 of influenza A virus (M2e) is highly conserved but poorly immunogenic and needs to be fused to an adjuvant protein or carrier virus-like particles (VLPs) to increase immunogenicity and provide protection against infection. In this study, we obtained VLPs based on capsid proteins (CPs) of single-stranded RNA phages Beihai32 and PQ465 bearing the M2e peptides. Four copies of the M2e peptide were linked to the C-terminus of the CP of phage Beihai32 and to the N and C termini of the CP of phage PQ465. The hybrid proteins, being expressed in Escherichia coli, formed spherical VLPs of about 30 nm in size. Immunogold transmission electron microscopy showed that VLPs formed by the phage PQ465 CP with a C-terminal M2e fusion present the M2e peptide on the surface. Subcutaneous immunization of mice with VLPs formed by both CPs containing four copies of the M2e peptide at the C termini induced high levels of M2e-specific IgG antibodies in serum and provided mice with protection against lethal influenza A virus challenge. In the case of an N-terminal fusion of M2e with the phage PQ465 CP, the immune response against M2e was significantly lower. CPs of phages Beihai32 and PQ465, containing four copies of the M2e peptide at their C termini, can be used to develop recombinant influenza A vaccine.

The influence of chemical structure spacings on the fluorocopolymers nano-organization

In ternary fluoropolymers Viton GFLT 600S and Viton GFLT 200S, more types of nanoformations with the size of 3–80 nm are found than in double SCF-26 and SCF-32, while their prehistory changes according to the X-ray diffraction analysis data in the region of large angles. This process is more influenced by the chemical structure of the junctions in the macromolecules than by the molecular weight. The complex and unequal character of change of dynamic viscosity of fluoropolymers with temperature increase is caused by multiple phase transitions. It is shown that fluorocarbon rubber SKF-32 does not transition to the viscous-fluid state up to ~190°C in contrast to three fluoropolymers due to intermolecular nanoformations of 5 nm in size, the strength of which is significantly higher than nanoformations of 3–4 nm in the latter. It was found that the rotational mobility of the TEMPO radical is determined not so much by the intermolecular distances in the disordered part of the copolymers as by the flexibility of the passing chains connecting the ordered formations into a single system.

Nonplanar Nanographene with a Large Conjugated π-Surface.

Conjugated π-surfaces are ubiquitous in molecules and materials. However, large π-surfaces up to a few nanometers in size are difficult to construct in an atomically precise manner. They tend to aggregate because of strong π-π interactions, resulting in notorious problems for both purification and spectroscopic investigations. Here, by contrast, we report the design, synthesis, and full characterizations of a nonplanar nanographene 1, which has a large, precise, and nonstacked π-surface. It is soluble in common organic solvents and allows for thorough investigations. The structure of 1, comprising 85 fused rings with an extended π-surface of 3 nm in size, is unambiguously confirmed by single-crystal X-ray diffraction. Unusual electronic structures, record-high near-infrared absorption, pronounced magnetic shielding, and ultrastrong heteromolecular van der Waals complexations are demonstrated, enabling us to establish a clear structure-property relationship, which has been elusive for decades. These results have broad implications for studying and understanding various phenomena and processes relevant to both discrete and interacting π-surfaces.

Co-delivery of Liposomal Ketoconazole and Bevacizumab for Synergistical Inhibition of Angiogenesis Against Endometrial Cancer.

In this study, we designed a novel formulation based on liposomes for the co-delivery of cancer-derived exosome inhibitor (ketoconazole, Keto) and angiogenesis inhibitor (bevacizumab, mAb). The designed Combo-Lipo formulation was systematically characterized, exhibiting a uniform average particle size of 100nm, as well as excellent serum and long-term physical stabilities. The cell viability assay revealed that Combo-Lipo treatment significantly reduced the viability of cancer cells compared to free drugs. Moreover, liposomes effectively inhibited angiogenic mediators and reduced tumor immune suppressive factors. The Combo-Lipo formulation demonstrated potent downregulation of angiogenic factors and synergistic effects in suppressing their production. Furthermore, liposomes inhibited tumor-associated macrophages (TAMs), leading to decreased expression of tumor-promoting factors. Together, these findings highlighted the promising characteristics of Combo-Lipo as a therapeutic formulation, including optimal particle size, serum stability, and potent anti-cancer effects, as well as inhibition of angiogenic mediators and TAMs toward treating endometrial cancer.

Citrus aurantifolia-derived carbon quantum dots with red fluorescence emission for codelivery with curcumin as theranostic liposomes for lung cancer

BackgroundCarbon dots (CDs) derived from Citrus aurantifolia represent a promising platform for advanced cancer therapy and diagnostics (theranostics). These CDs are synthesized through a sustainable and cost-effective hydrothermal method, utilizing fruit juice as a green carbon source. Despite the potential, research on the synthesis of citrus-based CDs, especially regarding their red fluorescence emission, which is crucial for enhanced tissue penetration and biomedical efficacy, remains limited.ResultsIn this study, CDs were successfully synthesized from C. aurantifolia fruit, yielding nanoparticles below 5 nm in size (PDI 0.231 ± 0.04). Characterization revealed favorable optical properties, including excitation-dependent fluorescent behavior with prominent red emission under higher excitation wavelengths, a quantum yield of 8.17%, and stable photoluminescence. Chemical composition analysis using XPS, FTIR, and XRD confirmed the purity and structure of the CDs.To explore their biomedical application, CDs were co-loaded with curcumin into liposomes. The formulations had a mean size of 177.2 ± 3.6 nm (PDI 0.270 ± 0.012), demonstrated efficient drug entrapment (60.32 ± 2.24%), and exhibited rapid release kinetics, with 90.21 ± 2.16% of the drug release within 8 h. In vitro studies using A549 lung cancer cells demonstrated superior cellular uptake and cytotoxicity of Cur-CD-loaded liposomes compared to curcumin alone (Cur-Suspension), achieving IC50 values of 0.093 ± 0.011 µg/ml and 0.016 ± 0.006 µg/ml, respectively.ConclusionThis research underscores C. aurantifolia as a viable natural source for green CD synthesis. The obtained CDs with red fluorescence emission, optimized through reaction conditions and excitation wavelengths, hold promise for enhanced biological applications, particularly in the realm of lung cancer therapy. The findings advocate for further exploration and refinement of citrus-based CDs as versatile theranostic agents, capitalizing on their sustainable origins and potent biomedical properties. The combination of citrus-derived CDs with curcumin loaded into liposomal formulations represents a potent theranostic strategy for lung cancer treatment, leveraging the unique properties of CDs and their potential for targeted and effective therapy.Graphical abstract

Ultrasmall Prussian Blue Nanozyme Attenuates Osteoarthritis by Scavenging Reactive Oxygen Species and Regulating Macrophage Phenotype.

Osteoarthritis (OA) is a degenerative joint disease characterized by obscure etiology and unsatisfactory therapeutic outcomes, making the development of new efficient therapies urgent. Superfluous reactive oxygen species (ROS) have historically been considered one of the crucial factors inducing the pathological progression of OA. Ultrasmall Prussian blue nanoparticles (USPBNPs), approximately sub-5 nm in size, are developed by regulating the configuration of polyvinylpyrrolidone chains. USPBNPs display an excellent ROS eliminating capacity and catalase-like activity, capable of decomposing hydrogen peroxide (H2O2) into O2. The anti-inflammatory mechanism of USPBNPs can be attributed to repolarizing macrophages from pro-inflammatory M1 to anti-inflammatory M2 phenotype by decreasing the ROS levels accompanied by O2 improvement. Additionally, USPBNPs exhibit an exciting therapeutic efficiency against OA, comparable to that of hydrocortisone in vivo. This study not only develops a new therapeutic agent for OA but also offers an estimable insight into the application of the nanozyme.

Reactive Oxygen Species-Regulated Conjugates Based on Poly(jasmine) Lactone for Simultaneous Delivery of Doxorubicin and Docetaxel.

In cancer therapy, it is essential to selectively release cytotoxic agents into the tumor to prevent the adverse effects associated with anticancer drugs. Thus, in this study, a stimuli-sensitive polymer-drug conjugate was synthesized for selective drug release. Doxorubicin (DOX) and docetaxel (DTX) were conjugated onto novel poly(jasmine lactone) based copolymer via a thioketal (TK) linker. In addition, a photosensitizer (chlorin e6) was attached to the polymer, which served as a reactive oxygen species generator to cleave the TK linker. The conjugate is readily self-assembled into micelles less than 100 nm in size. Micelles demonstrate a notable increase in their ability to cause cell death when exposed to near-infrared (NIR) light on MDA-MB-231 breast cancer cells. The increase in cytotoxicity is higher than that observed with the combination of free DOX and DTX. The accumulation of DOX in the nucleus after release from the micelles (laser irradiation) was also confirmed by confocal microscopy. In the absence of light, micelles did not show any toxicity while the free drugs were found toxic irrespective of the light exposure. The obtained results suggest the targeted drug delivery potential of micelles regulated by the external stimuli, i.e., NIR light.

Beta-cyclodextrin–Phyllanthus emblica emulsion for zinc oxide nanoparticles: Characteristics and photocatalysis

Abstract This study presents a new approach for producing zinc oxide nanoparticles (ZnONPs) utilizing an emulsion of beta-cyclodextrin (β-CD) and Phyllanthus emblica fruit extract. When synthesized, the particles were around 90 ± 5 nm in size. The zeta potential investigation yielded a value of −27.1 mV. The generated ZnONPs exhibited 83.70% anti-oxidant activity as well as good radical scavenging capabilities. The catalytic activity of ZnONPs was investigated using rhodamine B dye, and they displayed that maximum photocatalytic degradation was found to be 90.32% when exposed to UV light and 50.5% when not exposed to UV light. The kinetic investigation of photocatalytic degradation employs pseudo-first-order rate kinetics, with a rate constant of 2.5 × 10−2 under UV irradiation and 1.1 × 10−2 without irradiation. Anti-bacterial tests against Escherichia coli bacteria demonstrated the particles’ anti-bacterial characteristics. Anti-cancer studies were carried out using KB-31 cancer cells at varying particle concentrations. The studies confirmed that the particles produced are anti-cancer. In conclusion, this study reports a new green synthesis method to fabricate ZnONPs with high anti-microbial, anti-oxidant, and anti-cancer properties and suitable for various biomedical applications.

Characterization, stability, and skin application of astaxanthin particulates

PurposeAstaxanthin (AX), commonly used for dermal applications, exhibits anti-inflammatory and antioxidant activities; however, it has poor water solubility. In this study, we investigated the physicochemical properties of AX-containing particulates formulated using the amphiphilic graft copolymer Soluplus (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer: Sol) and polyethylene glycol-2000 (PEG 2000); in addition, the stability and skin applications of AX particulates were investigated.MethodsAX, Sol, and PEG were mixed by weight to prepare AX particles using the hydration method. The prepared particles were subjected to stability evaluations including particle size distribution, zeta potential estimation, and fluorescence spectroscopy as well as physical evaluations including 1H-1H NOESY NMR spectral measurement, powder X-ray diffraction, and differential scanning calorimetry. Functional evaluations included singlet oxygen scavenging, skin permeation test, and fluorescence microscopy.ResultsRelatively stable particles of Sol/AX and Sol/PEG 2000/AX, approximately 100 nm and 125 nm in size, respectively, were formed at a mixed weight ratio (9/1) of 0.1 M Ascorbic Acid solution (0.1 M ASC) and a mixed weight ratio (8/1/1) of 0.1 M ASC, respectively, at 25 °C after storage for 14 days under light-shielded condition. Stability evaluations revealed a decrease in fluorescence intensity and color fading for Sol/AX = 9/1 and Sol/PEG 2000/AX = 8/1/1 (dispersion medium: distilled water); however, no change in fluorescence intensity of AX was observed immediately after preparation in Sol/AX = 9/1 and Sol/PEG 2000/AX = 8/1/1 (dispersion medium: 0.1 M ASC). The fluorescence intensity of AX did not fluctuate significantly immediately after adjustment, and the particles remained stable, showing a bright orange color with time. NMR spectra of Sol/AX = 9/1 and Sol/PEG 2000/AX (dispersion medium: 0.1 M ASC) showed the interactions between the CH3 group e from Sol (1.8 ~ 2.0 ppm) and the CH groups H-15,11 from AX (6.7 ~ 6.8 ppm), 8’,12’ (6.4 ~ 6.5 ppm), H-10,14 (6.4 ~ 6.5 ppm), and 7,7’ (6.2 ~ 6.3 ppm), indicating the disappearance of cross peaks. Furthermore, new cross peaks were identified for the CH3 group e of Sol (1.8 ~ 2.0 ppm), the 7-membered ring z of Sol (1.5 ~ 1.8 ppm), the 5-membered ring S of ASC (3.5 ~ 3.6 ppm), the CH group T (3.8 ~ 3.9 ppm), and the CH group U (4.7 ppm). Fluorescence microscopy observations of microparticles formulated with Sol/PEG 2000/AX showed a slight improvement in skin penetration.ConclusionNew AX particulates were formed using Sol/PEG 2000/AX = 8/1/1, suggesting that Sol/PEG 2000/AX maintained the stability and improved the skin penetration of AX.

Exosomes of immune cell origin and their therapeutic potential for tumors

AbstractExosomes are nanoscale membrane vesicles identified by electron microscopy in 1946. They are approximately 30–150 nm in size. Originally, exosomes were thought to be used to eliminate excess components from cells to maintain their normal physiology. Later, it was found that the function and targeting of specific cellular components in exosomes have important implications for the regulation of cellular communication. In the last few years, exosomes have been linked to tumors, infections, and other diseases. New advances in cancer immunotherapy have occurred as a result of the identification of exosomes of immune cell origin, expanding the existing anticancer immune response. This article details exosomes derived from dendritic cells, T lymphocytes (CD4+ T cells, CD8+ T cells, and CAR‐T cells), natural killer cells, and their promising applications in tumor therapy.

TREATMENT FOR REMOVING ZN COMPOUNDS FROM SILICA-FILLED VULCANIZED RUBBER AND ANALYSIS OF SILICA AGGREGATE DISPERSION

ABSTRACT Treatment of silica-filled rubber vulcanizates with a diethyl ether/concentrated hydrochloric acid solution for 96 h at room temperature can remove most Zn compounds smaller than approximately 90 nm, which account for most of the residual ZnO, rubber-soluble Zn compounds and ZnS resulting from crosslinking reactions of by-products. However, a very small number of giant ZnO particles of a few micrometers in size remain after such treatment. In the silica-filled SBR matrix treated for 96 h, a significant increase in crosslink density and Young’s modulus was observed due to crosslinking reactions after HCl was removed from HCl-added rubber molecules. This increase in crosslink density was accompanied by an increase in the surrounding layer of bound rubber closest to the silica of the two bound rubber layers around it and a decrease in the rubber matrix of the same volume. It is inferred that there was little change in the aggregate structure of the silica due to these volume changes. Alternatively, ultra-small X-ray scattering measurements of the treated samples showed shoulders derived from silica aggregates and clear high-resolution X-ray computed microtomography (X-ray CT) images were obtained due to the removal of Zn compounds smaller than approximately 90 nm in size. The relationship between these shoulders and the size of silica aggregates obtained by X-ray CT imaging was qualitatively consistent, and it was not affected by the presence or absence of bis-(3-triethoxysilylpropyl) tetrasulfide and 1,3-diphenylguanidine, but was dependent on the rubber type. The distance between nearest neighbor particles of silica aggregates, determined by X-ray CT imaging, also depended on the types of rubber.

Co-delivery of Siape1 and Melatonin by 125I-loaded PSMA-targeted Nanoparticles for the Treatment of Prostate Cancer.

Both apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1) inhibition and melatonin suppress prostate cancer (PCa) growth. This study evaluated the therapeutic efficiency of self-assembled and prostate-specific membrane antigen (PSMA)-targeted nanocarrier loading 125I radioactive particles and encapsulating siRNA targeting APE1 (siAPE1) and melatonin for PCa. The linear polyarginine R12 polypeptide was prepared using Fmoc-Arg-Pbf-OH. The PSMA-targeted polymer was synthesized by conjugating azide-modified R12 peptide to PSMA monoclonal antibody (mAb). Before experiments, the PSMA-R12 nanocarrier was installed with melatonin and siAPE1, which were subsequently labeled by 125I radioactive particles. In vitro biocompatibility and cytotoxicity of nanocomposites were examined in LNCaP cells and in vivo biodistribution and pharmacokinetics were determined using PCa tumor-bearing mice. PSMA-R12 nanocarrier was ~120 nm in size and was increased to ~150 nm by melatonin encapsulation. PSMA-R12 nanoparticles had efficient loading capacities of siAPE1, melatonin, and 125I particles. The co-delivery of melatonin and siAPE1 by PSMA-R12-125I showed synergistic effects on suppressing LNCaP cell proliferation and Bcl-2 expression and promoting cell apoptosis and caspase-3 expression. Pharmacokinetics analysis showed that Mel@PSMA-R12-125I particles had high uptake activity in the liver, spleen, kidney, intestine, and tumor, and were accumulated in the tumor sites within the first 8 h p.i., but was rapidly cleared from all the tested organs at 24 h p.i. Administration of nanoparticles to PCa tumors in vivo showed that Mel@PSMA-R12- 125I/siAPE1 had high efficiency in suppressing PCa tumor growth. The PSMA-targeted nanocarrier encapsulating siAPE1 and melatonin is a promising therapeutic strategy for PCa and can provide a theoretical basis for patent applications.

Reactive Molecular Dynamics Simulations of Micrometeoroid Bombardment for Space Weathering of Asteroid (162173) Ryugu

Remote sensing observations by Hayabusa2 and laboratory measurements have revealed that the phyllosilicates on asteroid (162173) Ryugu are dehydrated/dehydroxylated due to space weathering. Reactive molecular dynamics simulations were performed to evaluate the magnitude of the dehydroxylation of Mg-rich serpentine by micrometeoroid impacts. When micrometeoroids were not coupled with interplanetary magnetic fields, serpentine could be dehydroxylated by micrometeoroids as small as 2 nm in size. In particular, ∼200 O–H bonds dissociated when the meteoroids were derived from cometary activity (the impact velocity was ∼20 km s−1). When nano-sized dust particles were accelerated to ∼300 km s−1 by the magnetic fields of solar wind plasma, the number of dissociated O–H bonds increased by 1 order of magnitude. Consequently, even 1 nm-sized dust particles can contribute to the space weathering of Ryugu. In all cases, Si–OH, H2O, and free OH were generated from the hydroxyls initially connected to Mg, which could partially offset dehydration. Despite the limitations of our computational resources, which restricted the simulation timescale to 1 ps, reactive molecular dynamic simulations demonstrated that micrometeoroid bombardment could influence the space weathering of asteroids.

Microstructure and mechanical characteristics of Al1050/B2O3+Cu hybrid surface nanocomposite fabricated using friction stir processing

Abstract In the realm of advanced materials engineering, the development of hybrid nanocomposites has garnered significant attention due to their superior mechanical properties and potential applications. The primary aim of this research is to develop a surface hybrid nanocomposite using Al1050 aluminium alloy (5 mm thickness) as the base material through friction stir processing. B2O3 nano-powder, averaging 100 nm in size, and Cu micro-powder, averaging 5 μm in size, were incorporated into the aluminium surface in various volume ratios using the Friction Stir Processing (FSP). The processing parameters included a tool rotational speed of 1250 rpm, a feed rate of 50 mm min−1, and a tilt angle of 3°. The number of passes was set at two levels: 1 and 3 passes. The influence of the volume ratio of constituents and the number of passes on the microstructure and mechanical properties of the resulting composite was thoroughly explored. The samples underwent tensile tests, microhardness tests, and metallographic examinations using both Optical Microscopy (OM) and Field Emission Scanning Electron Microscopy (FE-SEM). The composite with 25%-B2O3-75%-Cu composition exhibited the highest stress and hardness values, measuring 139 MPa and 58.14 HV, respectively. The enhanced strength of this sample is attributed to the presence of additives and the resultant grain size.

Study on the Synthesis of BTA@MSNs Nanocarriers

Abstract Mesoporous silica, characterized by its adjustable pore size, uniform distribution, stable structure, and non-toxicity, is widely used as an encapsulating material for corrosion inhibitors. This study initially established that, compared to the high-temperature calcination method, the removal of surfactants via the solvent extraction method yields mesoporous silica with uniform size and better dispersibility. Results from N2 adsorption-desorption tests indicated that the mesoporous silica prepared by the solvent extraction method had an average pore diameter of 2.41 nm, a volume of 0.42 cc/g, and a specific surface area of 69.73 m2/g. SEM and TEM analyses showed that the BTA@MSNs nanoparticles synthesized via a one-step method were approximately 100 nm in size, whereas those prepared by the vacuum loading method were about 50 nm, both exhibiting ordered mesoporous structures. UV-vis spectrophotometry results revealed that the loading capacity of BTA in the nanoparticles produced by the one-step synthesis method was significantly lower than that in the BTA@MSNs nanoparticles prepared via the vacuum impregnation method.

Structure and optical properties of ZnxCd1-xS and Cu:ZnxCd1-xS templated on DNA molecules

One-dimensional ZnxCd1−xS and Cu: Zn x Cd1−x S nanostructures were prepared using DNA as a template to promote growth along the molecular axis. The formation of homogeneously alloyed nanocrystals with cubic zinc blende-type structures was verified using x-ray diffraction and Raman spectroscopy. X-ray photoemission spectra revealed the presence of Cu(I) in the doped Cu: Zn x Cd1−x S nanocrystals. The effectiveness of the DNA template to direct the semiconductor growth in one dimension was demonstrated by AFM and TEM. The nanostructures displayed a granular morphology comprising nanoparticles with an average diameter of 14 nm composed of assemblies of smaller crystallites of 2.0 nm in size. Rope-like assemblies with an average diameter of 48 nm and extending in length to several hundred micrometres were obtained by evaporation-induced self-assembly. UV-Vis absorption and emission spectra indicated that the optical bandgaps (2.89–4.00eV) and photoluminescence peaks (608–819 nm) of the DNA-templated nanocrystals could be precisely controlled by modifying the molar ratios of their Zn/Cd precursors. Doping with Cu(I) gave an increase in photoluminescence intensity and a composition-independent red-shift of 0.23 eV. The preparation of DNA-templated Zn x Cd1−x S and Cu: Zn x Cd1−x S provides a simple, low-temperature route to aqueous dispersions of inorganic materials with controlled optical gap.

Solvent-free oxidation of alcohols by a heterogeneous Fe3O4@SiO2-DTPA-Ru nanocatalyst

A novel magnetic heterogeneous ruthenium catalyst (Fe3O4@SiO2-DTPA-Ru) was prepared by using magnetic silicon spheres as support, ethylenediaminepentaacetic acid (DTPA) as functional ligands, ruthenium chloride as catalyst precursor. The results obtained after a series of characterizations showed that the catalyst Fe3O4@SiO2-DTPA-Ru was 5–15 nm in size with a 0.205 nm lattice and contained 0.31 mmol Ru/g catalyst. It also had a good thermal stability under 232°C which was verified by thermal filtration method. Besides, the saturation magnetic intensity was as high as 20.54 emu/g. The catalyst Fe3O4@SiO2-DTPA-Ru was applied for the first time into thirteen oxidation reactions of aromatic alcohols and showed good catalytic activity even the yields of eleven aromatic alcohols were all over 90%. In catalyzing 1-phenylethanol to acetophenone, its TOF and TON were 9677 h−1 and 6991, respectively. The Fe3O4@SiO2-DTPA-Ru catalyst could still maintain good reusability and catalytic performance after 15 cycles of 1-phenylethanol oxidation, which was superior to many reported catalysts and had great potential in future industrial production.

Atomic-level insights into CeO2 performance: Chemical interactions in CMP explored through CeO2-SiO2 studies

This study explores the effects of atomic-level factors on the performance of CeO2 when interacting with SiO2 films. It specifically examines how different precursors, the ratio of Ce to OH, and reaction temperatures influence outcomes. Our findings reveal that smaller particles, around 5 nm in size, created using a Ce4+ precursor, are more effective at removing SiO2 films compared to larger, more crystalline particles from a Ce3+ precursor. This is due to their increased interaction with the SiO2 film during the polishing process, challenging the conventional emphasis on mechanical abrasion in chemical mechanical planarization (CMP) and highlighting the crucial role of chemical interactions. Further analysis through FT-IR and TGA-FTIR techniques showed distinct functional group profiles on the ceria surfaces. Ceria derived from Ce4+ exhibited a higher presence of OH and NO3 groups, enhancing adsorption capabilities, as verified by CHN analysis. Importantly, first-principles calculations identified these surface groups as key to improving adhesion to SiO2 films. Surfaces of amorphous CeO2, rich in -OH and -NO3 groups, showed significantly higher adhesion levels than their crystalline counterparts, connecting crystallinity to chemical functionality. This new insight leads to the possibility of designing next-generation CeO2 abrasives with increased chemical activity.

The green approach of chitosan/Fe2O3/ZnO-nanocomposite synthesis with an evaluation of its biological activities

Biopolymers embedded with nanoparticles of metal oxides (MOs) demonstrate a wide range of bio-functions. Chitosan-incorporated MOs are an interesting class of support matrices for enhancing the biological function, compared to other support matrices. Therefore, the importance of this study lies in exploiting chitosan as a carrier not of one metal as in previous studies, but of two metals in the form of a nanocomposite to carry out several biological functions. The coprecipitation approach was employed to synthesize chitosan/Fe2O3/ZnO-nanocomposite in the present research. The characterization of chitosan/Fe2O3/ZnO-nanocomposite was performed to find out the morphology and dispersion properties of chitosan/Fe2O3/ZnO-nanocomposite. The X-ray diffraction (XRD) investigation revealed that these were crystalline. Fourier transforms infrared (FTIR) spectrum bands were viewed at 400/cm and 900/cm, due to the stretching vibration of Fe and Zn oxygen bond. TEM showed that chitosan/Fe2O3/ZnO-nanocomposite was of 20–95 nm in size. chitosan/Fe2O3/ZnO-nanocomposite exhibited inhibitory potential against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Candida albicans with inhibition zones of 25 ± 0.1, 28 ± 0.2, 27 ± 0.1, and 27 ± 0.2 mm, respectively while didn’t inhibited Aspergillus niger. MIC value of nanocomposite was 15.62 ± 0.33 µg/mL for C. albicans, B. subtilis and E. coli, while it was 62.50 ± 0.66 µg/mL for Pseudomonas aeruginosa. Ranged values of nanocomposite MBC (15.62 ± 0.33 to 125 ± 1 µg/mL) were attributed to all tested bacteria. Different concentrations of chitosan/Fe2O3/ZnO-nanocomposite MBC (25, 50, and 75%) reflected anti-biofilm activity against E. coli (85.0, 93.2, and 96.0%), B. subtilis (84.88, 92.21, and 96.99%), S. aureus 81.64, 90.52, and 94.64%) and P. aurogenosa (90.11, 94.43, and 98.24%), respectively. The differences in the levels of antimicrobial activities may depend on the type of examined microbes. Antioxidant activity of chitosan/Fe2O3/ZnO-nanocomposite was recorded with excellent IC50 values of 16.06 and 32.6 µg/mL using DPPH and ABTS scavenging, respectively. Wound heal by chitosan/Fe2O3/ZnO-nanocomposite was achieved with 100% compared to the untreated cells (76.75% of wound closer). The cytotoxicity outcomes showed that the IC50 of the chitosan/Fe2O3/ZnO-nanocomposite was 564.32 ± 1.46 µg/mL normal WI-38 cells. Based on the achieved findings, the chitosan/Fe2O3/ZnO-nanocomposite is a very promising agent for perform pharmacological activities.