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This work reports the rheological properties of an acrylic aqueous dispersion filled with hollow aluminosilicate microspheres and highly dispersed amorphous silicon dioxide studied by using rotational viscometry. It was established that an increase in the degree of filling with hollow microspheres leads to a significant increase in the viscosity of the aqueous dispersion, which results in technological difficulties when applying coatings to the surface. The introduction of a small amount of silicon dioxide additive leads to a decrease in the structural strength and effective viscosity of the aqueous dispersion of the acrylic copolymer, which allows significantly reducing the viscosity and regulating the rheological characteristics of highly filled systems, which is decisive in the technology of their application. The combination of such fillers as silicon dioxide and hollow aluminosilicate microspheres in an aqueous dispersion of an acrylic copolymer allows simultaneously reaching a number of positive phenomena: a reduction in the viscosity of the material during application (without dilution) due to the use of high shear rates and an increase in the rate of dispersion structuring after application, and also allows achieving sedimentation resistance during storage and transportation. [ABSTRACT FROM AUTHOR]

Silicon dioxide (SiO2), a new type of inorganic nonmetallic material, has been widely used in people's livelihood and military industry. For silicon dioxide-based applications, ultra-precision micromachining is a crucial component that impacts the performance of the finished products. This research reports the precise micromachining of silicon dioxide wafers by femtosecond laser. A prediction model for groove processing size is developed, and an experiment is carried out to investigate the silicon dioxide groove processing technology. The effects of processing parameters that include laser power, scanning speed, scanning repetitions, and defocus amount on the processed properties of grooves, the heat affected zone, and processed roughness are discussed. The variable defocus processing method is proposed, which can effectively improve the inclination angle of the groove wall and the quality of the machined groove. Moreover, scanning electron microscopy is used to analyze the groove morphology, allowing for the improvement of surface quality and processing parameter optimization. [ABSTRACT FROM AUTHOR]

For the first time, the nanocomposites from glycine sodium nitrate (GSN) and nanoparticles of silicon dioxide (nSiO2) have been synthesized using a slow evaporation technique. Observed that the optimal content of nSiO2 was estimated as 16.7 wt.%, any deviation from which affected the growth of GSN crystals in the composite, phase transition temperature, dielectric constant, and characteristics of dielectric hysteresis loops. All the anomalies will be thoroughly explained with the evidence of structural data of X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). [ABSTRACT FROM AUTHOR]

Atomic and ionic single-bubble sonoluminescence of dysprosium was first recorded in bubble-movement mode in a standing ultrasonic wave in a colloidal dodecane suspension of SiO2 nanoparticles containing DyCl3 as a part of research on the development of sonoluminescent spectroscopy. Lines of Dy and Dy+ together with molecular SiO lines were recorded in the region 350–450 nm in this sonoluminescence spectrum with a resolution of Δλ = 1 nm and were due to the entry of nanoparticles into the bubble during sonolysis of the suspension and subsequent collisional excitation of emitters in the bubble plasma. Dy3+ luminescence bands with maxima at 477 and 570 nm that appeared by the same excitation mechanism were recorded at spectral resolution Δλ = 10 nm. An electron temperature Te = 7000 ± 300 K was found in the nonequilibrium plasma that occurred during bubble collapse, when Dy atoms and ions emitted light, by comparing the experimental and temperature-dependent calculated spectra of Dy and Dy+. [ABSTRACT FROM AUTHOR]

The effect of additions of SiO2 nanoparticles (the average size 100 nm; the concentration 0.3 and 3 g/liter) into an alkaline-phosphate-silicate electrolyte on the characteristics of the oxide layer formed by plasma-electrolytic oxidation (PEO) on AK7 silumin is studied. The concentration of the nanoparticles is shown to affect nonlinearly the phase composition, the proportion of the amorphous phase, the characteristics of the crystallites (the sizes and the microstresses), the layer thickness and the hardness, the wear resistance, and the corrosion resistance of the oxide layers. The less defective and the thickest layer and the highest protective properties, wear resistance and hardness are observed in the oxide layers formed when the concentration of nanoparticles in the electrolyte is 0.3 g/liter. These layers are also characterized by a minimum fraction of amorphous phase and largest mullite crystallites. [ABSTRACT FROM AUTHOR]

Throughout the period of operation of non-ferrous metal deposits, a significant amount of waste has been accumulated. The accumulated waste contains valuable metals in concentrations that allow considering them as valuable raw materials. However, it is worth noticing the presence of problems that previously did not allow for more complete extraction of the target components. Such problems include the presence of significant amounts of silicon dioxide in the form of a silicate matrix, the removal of which will allow the extraction of valuable components with the elimination of industrial waste areas. The paper considers a method for removing silicon from the polymetallic slags. According to the results of the work, it was found that silicon passes into solution in the form of ammonium hexafluorosilicate. Iron, aluminum, and a number of other components react with ammonium hydrofluoride, but do not leach into the solution due to their low solubility in the resulting system. After removing silicon, the solid residue was subjected to pyrohydrolysis to obtain a product that can be subjected to magnetic separation to obtain a magnetic iron concentrate and a non-ferrous metal concentrate. The formed concentrate can later be used to extract zinc, lead, silver, etc. The productive solution was directed to the deposition of silicon with the subsequent production of silicon dioxide. The resulting solution can be directed to evaporation in order to regenerate and reuse ammonium hydrodifluoride. [ABSTRACT FROM AUTHOR]

Link for citation: Korovkin M.V., Ananyeva L.G., Zherlitsyn A.A., Kondratiev S.S., Savinova O.V., Kurskaya V.S. Assessment of crystallinity degree of quartz raw materials. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 8, рр. 59-67. In Rus. The relevance of research is determined by the need to assess the degree of transformation of quartz raw materials in its natural occurrence, as well as, changes in the properties of raw materials and products are exploited under various operating conditions. X-ray diffraction and Infrared spectroscopy was used to assess the degree of crystallinity of various crystalline quartz materials and products made of silicon dioxide, which showed satisfactory convergence of results and can be recommended for use in world practice. Objects: artificially grown quartz, including samples of synthetic quartz with an admixture of aluminum, zone-colored single crystal of quartz with an admixture of two and ferric iron; natural crystals of amethyst, smoky quartz, optical quartz; samples of fused quartz, products made of technical and optical quartz and silicate glass; as well as fine-grained samples of quartzites, including their micro- and nano-sized fractions. Methods: optical and electron scanning microscopy, X-ray spectral and analysis, infrared spectroscopy, X-ray diffraction. Results. The paper shows that the degree of crystallinity of quartz raw materials and products based on it is determined by the presence of a structural ordering in the near zone that characterizes the crystalline state corresponding to the a-quartz phase, which is confidently recorded by XRD and FTIR methods. The local disorder of high-purity quartz or quartzites having various impurities or defects in their structure that arise under the influence of external influences or exploitation causes deterioration of their properties and decrease in the degree of crystallinity.

Negative bias temperature instability is regarded as one of the most important reliability concerns of highly scaled PMOS transistors. As a consequence of the continuous downscaling of semiconductor devices this issue has become even more important over the last couple of years due to the high electric fields in the oxide and the routine incorporation of nitrogen. During negative bias temperature stress a shift in important parameters of PMOS transistors, such as the threshold voltage, subthreshold slope, and mobility is observed. Modeling efforts date back to the reaction-diffusion model proposed by Jeppson and Svensson thirty years ago which has been continuously refined since then. Although the reaction-diffusion model is able to explain many experimentally observed characteristics, some microscopic details are still not well understood. Recently, various alternative explanations have been put forward, some of them extending, some of them contradicting the standard reaction-diffusion model. We review these explanations with a special focus on modeling issues.

Bed bugs are considered a major public health problem in industrialized countries. Usually, bed bug infestations are managed using a combination of physical and chemical methods. In recent years, new strategies for bed bug control have emerged, particularly the use of dusts like diatomaceous earth and silicon dioxide. However, in Europe, the use of silicon dioxide is restricted to professional, while diatomaceous earth can be harmful to the lungs. This study aimed to assess bed bug mortality rates associated with Sommières earth, green clay, talc, and sodium bicarbonate compared to silicon dioxide and diatomaceous earth from a pest management company, diatomaceous earth for litter conditioner, and diatomaceous earth from a supermarket. We tested permanent exposure, short exposure, horizontal transfer and repellent effect on two bed bug colonies. Sommières earth demonstrated efficacy ranging from 75% to 100% in permanent and short exposures, similar to the efficacy of diatomaceous earth from the pest management company. On the contrary, diatomaceous earth for litter conditioner and diatomaceous earth from a supermarket, green clay, talc, and sodium bicarbonate were found to be ineffective. This study demonstrates, for the first time, the efficacy of Sommières earth against bed bugs, but also highlights the variability in efficacy of diatomaceous earths on bed bugs depending on their quality.

The processes of synthesis of silicon carbide from natural mineral raw materials - diatomite mixed with coke (or coal, or graphite) have been studied. High-temperature heating was carried out using a flow of concentrated solar radiation (CSI) of high density (200 W/cm 2 ). The mixture was placed in a graphite crucible mounted on the focal zone of the Large Solar Furnace. The crucible with the material sample after irradiation with the XI flow was cooled in an arbitrary manner for 30 minutes. The analysis showed that such a diffraction pattern is due to the presence of three phases - silicon carbide β- SiC with a cubic system with lattice parameters a = 4.36 A and α- SiC with a hexagonal lattice with parameters a = 3.07 A c = 15.11 A, as well as graphite C of the hexagonal system.

The condition of architectural monuments is directly influenced by various factors, such as anthropogenic, natural, and technological, leading to the degradation of both structures and construction materials, ultimately resulting in irreversible damage. These factors diminish the quality of construction materials, contributing to alterations and the destruction of the appearance and structure of white stone. The primary objective of this research is to develop cement-free compositions for restoring ancient masonry materials. Tests were conducted at the BM Department of VlSU using modern equipment. New material compositions for restoration have been devised, combining lime and silicon dioxide with chemical additives to enhance adhesive and strength properties. Adhesive strength increases by 1.5 times with the addition of white soot (silicon dioxide). Moreover, the incorporation of silicon dioxide positively impacts compressive strength (from 10.6 to 15.6 MPa), surpassing the strength of composites without white soot by 1.5 times. XRD confirms the developed composite’s similar phase composition to white stone, supported by optical microscopy and SEM results. Restoration composites based on these compositions exhibit homogeneous structures compatible with white stone and demonstrate high adhesion levels. These results make the proposed compositions promising for white stone restoration, ensuring structural and chemical compatibility with the restored surface.

Nanoparticles have been extensively used to deliver therapeutic drugs to tumor tissues through the extravasation of a leaky vessel via enhanced permeation and retention effect (EPR, passive targeting) or targeted interaction of tumor-specific ligands (active targeting). However, the therapeutic efficacy of drug-loaded nanoparticles is hampered by its heterogeneous distribution owing to limited penetration in tumor tissue. Inspired by the fact that cancer cells can recruit inflammatory immune cells to support their survival, we developed a click reaction-assisted immune cell targeting (CRAIT) strategy to deliver drug-loaded nanoparticles deep into the avascular regions of the tumor. Immune cell-targeting CD11b antibodies are modified with trans-cyclooctene to enable bioorthogonal click chemistry with mesoporous silica nanoparticles functionalized with tetrazines (MSNs-Tz). Sequential injection of modified antibodies and MSNs-Tz at intervals of 24 h results in targeted conjugation of the nanoparticles onto CD11b+ myeloid cells, which serve as active vectors into tumor interiors. We show that the CRAIT strategy allows the deep tumor penetration of drug-loaded nanoparticles, resulting in enhanced therapeutic efficacy in an orthotopic 4T1 breast tumor model. The CRAIT strategy does not require ex vivo manipulation of cells and can be applied to various types of cells and nanovehicles.

ObjectiveExposure to inhaled mineral dust, in particular silica, is associated with increased odds of rheumatoid arthritis (RA) and other autoimmune diseases. We studied the association of RA with work-related coal and silica exposure in the Appalachian region of the US.MethodsWe carried out a random-digit dialed telephone survey in selected counties in Appalachia that had elevated coal workers' pneumoconiosis mortality. Our study cohort included men ages ≥50 with any employment history, and we assessed exposure to coal mining employment, other work-related dust, and ergonomic factors. We ascertained self-reported physician diagnosis of any arthritis and of RA with glucocorticoid treatment. We used multivariable logistic regression analysis to estimate the odds ratios (ORs) and associated population attributable fraction (PAF) estimates.ResultsAmong the 973 men who met study entry criteria (mean ± SD ages 66 ± 10 years; 54% ever smokers), 266 (27%) reported coal mining work and 189 (19%) reported other work-related silica exposure. There were 517 men (53%), who reported any arthritis and 112 (12%) whose disease met the study definition of RA. Adjusting for covariates, coal mining was associated with elevated odds of RA (OR 3.6 [95% confidence interval (95% CI) 2.1-6.2]), which accounted for a PAF of 33% (95% CI 26-40%) of the men studied. For any arthritis, the coal mining-associated OR was 2.3 (95% CI 1.6-3.2), with an associated PAF of 20% (95% CI 14-25%).ConclusionIn this population of older males living in a coal mining region, we estimated that 20% of arthritis and 33% of RA may be attributable to coal mining work.

Mitigation of the foreign body response (FBR) and successful tissue integration are essential to ensuring the longevity of implanted devices and biomaterials. The use of porous materials and coatings has been shown to have an impact, as the textured surfaces can mediate macrophage interactions with the implant and influence the FBR, and the pores can provide space for vascularization and tissue integration. In this study, we use a new class of implantable porous biomaterials templated from bicontinuous interfacially jammed emulsion gels (bijels), which offer a fully percolating, non-constricting porous network with a uniform pore diameter on the order of tens of micrometers, and surfaces with consistent curvature. We demonstrate that these unique morphological features, inherent to bijel-templated materials (BTMs), can enhance tissue integration and vascularization, and reduce the FBR. Cylindrical polyethylene glycol diacrylate (PEGDA) BTMs, along with PEGDA particle-templated materials (PTMs), and non-templated materials (NTMs), were implanted into the subcutaneous space of athymic nude mice. After 28 days, implants were retrieved and analyzed via histological techniques. Within BTMs, blood vessels of increased size and depth, changes in collagen deposition, and increased presence of pro-healing macrophages were observed compared to that of PTM and NTM implants. Bijel templating offers a new route to biomaterials that can improve the function and longevity of implantable devices. STATEMENT OF SIGNIFICANCE: All implanted biomaterials are subject to the foreign body response (FBR) which can have a detrimental effect on their efficacy. Altering the surface chemistry can decrease the FBR by limiting the amount of proteins adsorbed to the implant. This effect can be enhanced by including pores in the biomaterial to allow new tissue growth as the implant becomes integrated in the body. Here, we introduce a new class of self-assembled biomaterials comprising a fully penetrating, non-constricting pore phase with hyperbolic (saddle) surfaces for enhanced tissue integration. These unique morphological characteristics result in dense blood vessel formation and favorable tissue response properties demonstrated in a four-week implantation study.

Treatment of liver metastasis experiences slow progress owing to the severe side effects. In this study, we demonstrate a strategy capable of eliminating metastatic cancer cells in a selective manner. Nucleus-targeting W18O49 nanoparticles (WONPs) are conjugated to mitochondria-selective mesoporous silica nanoparticles (MSNs) containing photosensitizer (Ce6) through a Cathepsin B-cleavable peptide. In hepatocytes, upon the laser irradiation, the generated singlet oxygen species are consumed by WONPs, in turn leading to the loss of their photothermally heating capacity, thereby sparing hepatocyte from thermal damage induced by the laser illumination. By contrast, in cancer cells, the cleaved peptide linker allows WONPs and MSNs to respectively target nucleus and mitochondria, where the therapeutic powers could be unleashed, both photodynamically and photothermally. This ensures the energy production of cancer cells can be abolished. We further assess the underlying molecular mechanism at both gene and protein levels to better understand the therapeutic outcome.

Stem cell therapy in heart disease is challenged by mis-injection, poor survival, and low cell retention. Here, we describe a biocompatible multifunctional silica-iron oxide nanoparticle to help solve these issues. The nanoparticles were made via an in situ growth of Fe3O4 nanoparticles on both the external surfaces and pore walls of mesocellular foam silica nanoparticles. In contrast to previous work, this approach builds a magnetic moiety inside the pores of a porous silica structure. These materials serve three roles: drug delivery, magnetic manipulation, and imaging. The addition of Fe3O4 to the silica nanoparticles increased their colloidal stability, T2-based magnetic resonance imaging contrast, and superparamagnetism. We then used the hybrid materials as a sustained release vehicle of insulin-like growth factor-a pro-survival agent that can increase cell viability. In vivo rodent studies show that labeling stem cells with this nanoparticle increased the efficacy of stem cell therapy in a ligation/reperfusion model. The nanoparticle-labeled cells increase the mean left ventricular ejection fraction by 11 and 21% and the global longitudinal strain by 24 and 34% on days 30 and 60, respectively. In summary, this multifunctional nanomedicine improves stem cell survival via the sustained release of pro-survival agents.

Mesoporous silica nanoparticles (MSNs) are delivery vehicles that can carry cargo molecules and release them on command. The particles used in the applications reported in this Account are around 100 nm in diameter (about the size of a virus) and contain 2.5 nm tubular pores with a total volume of about 1 cm3/g. For the biomedical applications discussed here, the cargo is trapped in the pores until the particles are stimulated to release it. The challenges are to get the particles to the site of a disease and then to deliver the cargo on command. We describe methods to do both, and we illustrate the applicability of the particles to cure cancer and intracellular infectious disease. Our first steps were to design multifunctional nanoparticles with properties that allow them to carry and deliver hydrophobic drugs. Many important pharmaceuticals are hydrophobic and cannot reach the diseased sites by themselves. We describe how we modified MSNs to make them dispersible, imagable, and targetable and discuss in vitro studies. We then present examples of surface modifications that allow them to deliver large molecules such as siRNA. In vivo studies of siRNA delivery to treat triple-negative breast and ovarian cancers are presented. The next steps are to attach nanomachines and other types of caps that trap drug molecules but release them when stimulated. We describe nanomachines that respond autonomously (without human intervention) to stimuli specific to disease sites. A versatile type of machine is a nanovalve that is closed at neutral (blood) pH but opens upon acidification that occurs in endolysosomes of cancer cells. Another type of machine, a snap-top cap, is stimulated by reducing agents such as glutathione in the cytosol of cells. Both of these platforms were studied in vitro to deliver antibiotics to infected macrophages and in vivo to cure and kill the intracellular bacteria M. tuberculosis and F. tularensis. The latter is a tier 1 select agent of bioterrorism. Finally, we describe nanomachines for drug delivery that are controlled by externally administered light and magnetic fields. A futuristic dream for nanotherapy is the ability to control a nano-object everywhere in the body. Magnetic fields penetrate completely and have spatial selectivity governed by the size of the field-producing coil. We describe how to control nanovalves with alternating magnetic fields (AMFs) and superparamagnetic cores inside the MSNs. The AMF heats the cores, and temperature-sensitive caps release the cargo. In vitro studies demonstrate dose control of the therapeutic to cause apoptosis without overheating the cells. Nanocarriers have great promise for therapeutic applications, and MSNs that can carry drugs to the site of a disease to produce a high local concentration without premature release and off-target damage may have the capability of realizing this goal.

Microbial food safety of raw or minimally processed fresh produce is a significant challenge. The current sanitation processes are effective for inactivation of bacteria in wash water but have limited efficacy (5-log reduction) in the presence of relatively high organic content (chemical oxygen demand of 500 mg/liter), demonstrating a potential to address a significant unmet need to improve fresh produce sanitation. The particle-based sanitizer had no significant effect on the quality of fresh lettuce.IMPORTANCE The limitation of current sanitation processes for inactivation of microbes on the surfaces of fresh produce is due to nonspecific consumption of sanitizers by reactions with the food matrix and complexity of surface chemistries and structural features of produce surfaces. This study demonstrates a novel approach to enhance sanitation effectiveness of fresh produce using a particle-based sanitizer. The particle-based sanitizer concept provides localized high concentration delivery of chlorine to the surfaces of fresh produce and enables more than 5 logs of inactivation of inoculated bacteria on fresh produce surfaces without significant changes in produce quality. The results of this study illustrate the potential of this approach to address the unmet need for improving sanitation of fresh produce. Further validation of this approach using a scaled-up produce washing system will enable commercialization of this novel concept.

Nanoparticles' enhanced permeation and retention (EPR) variations due to tumor heterogeneity in naturally occurring brain tumors are commonly neglected in preclinical nanomedicine studies. Recent pathological studies have shown striking similarities between brain tumors in humans and dogs, indicating that canine brain tumors may be a valuable model to evaluate nanoparticles' EPR in this context. We recruited canine clinical cases with spontaneous brain tumors to investigate nanoparticles' EPR in different brain tumor pathologies using surface-enhanced Raman spectroscopy (SERS). We used gold nanoparticles due to their surface plasmon effect that enables their sensitive and microscopic resolution detection using the SERS technique. Raman microscopy of the resected tumors showed heterogeneous EPR of nanoparticles into oligodendrogliomas and meningiomas of different grades, without any detectable traces in necrotic parts of the tumors or normal brain. Raman observations were confirmed by scanning electron microscopy (SEM) and X-ray elemental analyses, which enabled localization of individual nanoparticles embedded in tumor tissues. Our results demonstrate nanoparticles' EPR and its variations in clinically relevant, spontaneous brain tumors. Such heterogeneities should be considered alongside routine preoperative imaging and histopathological analyses in order to accelerate clinical management of brain tumors using nanomedicine approaches.

ObjectivesIn a genome-wide association study, we discovered chromosome 12q15 (defined as rs73329476) as a silica-related pneumoconiosis susceptibility region. However, the causal variants in this region have not yet been reported.MethodsWe systematically screened eight potentially functional single-neucleotide polymorphism (SNPs) in the genes near rs73329476 (carboxypeptidase M (CPM) and cleavage and polyadenylation specific factor 6 (CPSF6)) in a case-control study including 177 cases with silicosis and 204 healthy controls, matched to cases with years of silica dust exposure. We evaluated the associations between these eight SNPs and the development of silicosis. Luciferase reporter gene assays were performed to test the effects of selected SNP on the activity of CPM in the promoter. In addition, a two-stage case-control study was performed to investigate the expression differences of the two genes in peripheral blood leucocytes from a total of 64 cases with silicosis and 64 healthy controls with similar years of silica dust exposure as the cases.ResultsWe found a strong association between the mutant rs12812500 G allele and the susceptibility of silicosis (OR=1.45, 95% CI 1.03 to 2.04, p=0.034), while luciferase reporter gene assays indicated that the mutant G allele of rs12812500 is strongly associated with increased luciferase levels compared with the wild-type C allele (p

Air pollution poses a significant threat to the environment and human health. Most in vivo health studies conducted regarding air pollutants, including particulate matter (PM) and gas phase pollutants, have been either through traditional medical intranasal treatment or using a tiny chamber, which limit animal activities. In this study, we designed and tested a large, whole-body, multiple animal exposure chamber with uniform dispersion and exposure stability for animal studies. The chamber simultaneously controls particle size distribution and PM mass concentration. Two different methods were used to generate aerosol suspension through either soluble material (Alternaria extract), liquid particle suspension (nanosilica solution), or dry powder (silica powder). We demonstrate that the chamber system provides well controlled and characterized whole animal exposures, where dosage is by inhalation of particulate matter.

PurposeIn this study, the efficacy of transurethral prostate ablation in the presence of silica-shell ultrasound-triggered phase-shift emulsions (sUPEs) doped with MR contrast was evaluated. The influence of sUPEs on MR imaging assessment of the ablation zone was also investigated.MethodssUPEs were doped with a magnetic resonance (MR) contrast agent, Gd2 O3 , to assess ultrasound transition. Injections of saline (sham), saline and sUPEs alone, and saline and sUPEs with Optison microbubbles were performed under guidance of a prototype interventional MRI navigation platform in a healthy canine prostate. Treatment arms were evaluated for differences in lesion size, T1  contrast, and temperature. In addition, non-perfused areas (NPAs) on dynamic contrast-enhanced (DCE) MRI, 55°C isotherms, and areas of 240 cumulative equivalent minutes at 43°C (CEM43 ) dose or greater computed from MR thermometry were measured and correlated with ablated areas indicated by histology.ResultsFor treatment arms including sUPEs, the computed correlation coefficients between the histological ablation zone and the NPA, 55°C isotherm, and 240 CEM43 area ranged from 0.96-0.99, 0.98-0.99, and 0.91-0.99, respectively. In the absence of sUPEs, the computed correlation coefficients between the histological ablation zone and the NPA, 55°C isotherm, and 240 CEM43 area were 0.69, 0.54, and 0.50, respectively. Across all treatment arms, the areas of thermal tissue damage and NPAs were not significantly different (P = 0.47). Areas denoted by 55°C isotherms and 240 CEM43 dose boundaries were significantly larger than the areas of thermal damage, again for all treatment arms (P = 0.009 and 0.003, respectively). No significant differences in lesion size, T1 contrast, or temperature were observed between any of the treatment arms (P > 0.0167). Lesions exhibiting thermal fixation on histological analysis were present in six of nine insonations involving sUPE injections and one of five insonations involving saline sham injections. Significantly larger areas (P = 0.002), higher temperatures (P = 0.004), and more frequent ring patterns of restricted diffusion on ex vivo diffusion-weighted imaging (P = 0.005) were apparent in lesions with thermal fixation.ConclusionsT1 contrast suggesting sUPE transition was not evident in sUPE treatment arms. The use of MR imaging metrics to predict prostate ablation was not diminished by the presence of sUPEs. Lesions generated in the presence of sUPEs exhibited more frequent thermal fixation, though there were no significant changes in the ablation areas when comparing arms with and without sUPEs. Thermal fixation corresponded to some qualitative imaging features.

Irinotecan is a key chemotherapeutic agent for the treatment of colorectal (CRC) and pancreatic (PDAC) cancer. Because of a high incidence of bone marrow and gastrointestinal (GI) toxicity, Onivyde (a liposome) was introduced to provide encapsulated irinotecan (Ir) delivery in PDAC patients. While there is an ongoing clinical trial (NCT02551991) to investigate the use of Onivyde as a first-line option to replace irinotecan in FOLFIRINOX, the liposomal formulation is currently prescribed as a second-line treatment option (in combination with 5-fluorouracil and leucovorin) for patients with metastatic PDAC who failed gemcitabine therapy. However, the toxicity of Onivyde remains a concern that needs to be addressed for use in CRC as well. Our goal was to custom design a mesoporous silica nanoparticle (MSNP) carrier for encapsulated irinotecan delivery in a robust CRC model. This was achieved by developing an orthotopic tumor chunk model in immunocompetent mice. With a view to increase the production volume and to expand the disease applications, the carrier design was improved by using an ethanol exchange method for coating of a supported lipid bilayer (LB) that entraps a protonating agent. The encapsulated protonating agent was subsequently used for remote loading of irinotecan. The excellent irinotecan loading capacity and stability of the LB-coated MSNP carrier, also known as a "silicasome", previously showed improved efficacy and reduced toxicity when compared to an in-house liposomal carrier in a PDAC model. Intravenous injection of the silicasomes in a well-developed orthotopic colon cancer model in mice demonstrated improved pharmacokinetics and tumor drug content over free drug and Onivyde. Moreover, improved drug delivery was accompanied by substantially improved efficacy, increased survival, and reduced bone marrow and GI toxicity compared to the free drug and Onivyde. We also confirmed that the custom-designed irinotecan silicasomes outperform Onivyde in an orthotopic PDAC model. In summary, the Ir-silicasome appears to be promising as a treatment option for CRC in humans based on improved efficacy and the carrier's favorable safety profile.

Surfactant controlling the wettability of reservoir rocks is one of the important ways to enhance oil recovery in low-permeability tight reservoirs. A large number of scholars have developed a series of excellent wettability control reagents through macro physical simulation experiments, but macro experiments are difficult to analyze the micro mechanism of liquid/liquid and liquid/solid interface action of reagents controlling rock wettability. In this paper, the wetting behavior of water molecules on silica surfaces modified with different hydroxylation, methylation and hydrophobic chain length was studied by molecular dynamics simulation, and the quantitative relationship between different modification degrees and wetting angle was established. The results show that the original wetting angle of silica is 58.5°, and the surface wettability can be changed from hydrophilic to hydrophobic through surface modification, with a wetting angle of 27.25°∼115.78°. With the increase of the coverage of hydrophobic methyl or hydrophilic hydroxyl modified groups, the wetting angle increases or decreases respectively. The quantitative relationship between modification degree and wetting angle was established by simulated data. With the increasing of the chain length of methyl group, the distance between water molecule and silica surface increases and the interaction decreases, which can improve the regulation effect of methyl group hydrophobicity. This paper provides a reference basis for the synthesis of rock wettability control reagent and the quantitative characterization of modification degree.

With the increase in environmental pollution, studies on the use of sustainable resources are increasing day by day. For this purpose, the use of natural fiber-reinforced polymer composites is encouraged in many areas such as automotive, transportation, construction, and home textiles. However, they are flammable and therefore seriously threaten the safety of people and property. Various flame retardant additives have been used to improve the flame retardancy properties of these composites. In this study, silicon dioxide (SD) and zinc borate (ZB) microparticles in different weight percentages (3, 5, 7, and 10%) were reinforced to give flame retardant properties to jute-epoxy composites. In addition, composites containing both SD and ZB microparticles were produced and they were labeled as HB. Then, thermal conductivity, flammability, water absorption, and mechanical properties of these composites were investigated. The burning rate of the composites decreased as the amount of microparticle increased. 5ZB5SD, including %5 SD and %5 SD microparticles, showed 36.60% less burning rate than the neat jute-epoxy composite. 5ZB showed 10.84% higher tensile strength than the neat jute-epoxy. The impact strength of the specimens increased with the increase in the filling ratio, and 5ZB5SD showed approximately 2.50 times the impact strength of the jute-epoxy composite.

This study was conducted to determine whether the simultaneous injections of Ar+ ions and tetraethyl orthosilicate (TEOS) to a substrate are able to fabricate a film on the substrate. The Ar+ ion energy was 100 eV. After the injections, we found a film deposited on the substrate. Following the analyses of the film with X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy, it was found that the deposited film was silicon dioxide (SiO2). We conclude that the low-energy Ar+ ion-beam-induced deposition method using TEOS is useful for the growth of SiO2 films.

α -cristobalite (α -C) is a polymorph of silica, mainly found in space exploration and geochemistry research. Due to similar densities, α -C is often used as a proxy for amorphous SiO 2 , particularly in computer simulations of SiO 2 surfaces and interfaces. However, little is known about the properties of α -C and its basic oxygen defects. Using density functional theory (DFT) simulations we provide a comprehensive report on the properties of perfect structure and oxygen vacancies in α -C. The calculated properties of α -C are compared with those of the better-characterized α -quartz (α -Q). Our results demonstrated that the positively charged O vacancy in α -C is most stable in the dimer configuration, in contrast to α -Q, which favors the puckered configuration. A back-projected configuration was also predicted in both polymorphs. We calculated the optical transition energies and isotropic hyperfine constants for O vacancies in both α -Q and α -C, and compared our findings with the results of previous studies and experiments. This work, thus, offers one of the first in-depth investigations of the properties of oxygen vacancies in α -C. [ABSTRACT FROM AUTHOR]

The process of single-stage synthesis of composite nanoparticles of titanium dioxide and silicon dioxide in the working zone of a plasmochemical reactor is modeled with the use of the chloride method based on joint oxidation of titanium and silicon tetrachlorides. The synthesis model takes into account the possibility of aggregation not only of titanium dioxide particles forming composite particle cores, but also of silicon dioxide particles, which do not participate in the formation of particle shells. The results predicted by various models (core size, shell thickness, and number of particles of various types) are compared. [ABSTRACT FROM AUTHOR]

Alumina-silicon carbide (Al2O3-SiC) composite powder (ASCP) was synthesized by molten salt method with silicon dioxide, carbon black, and Al powder as starting materials and NaCl and KCl together as molten salt medium. Effects of temperature and holding time on the phase composition and morphology were systematically investigated. Possible reactions involved in synthesis process of Al–Si–O–C system were analyzed by thermodynamic calculation, and synthesis mechanism was discussed. As-prepared ASCP was utilized to fabricate Al2O3-SiC composite bulk materials by pressureless route. Results show that molten salt is an essential factor to lower synthesis temperature. ASCP was synthesized at 1300 °C by heating for 4 h and template mechanism was found to play an important role. The bulk sample obtained by sintering at 1500 °C for 4 h attained apparent porosity of 42.3%, bulk density of 1.81 g cm−3, and higher compressive strength of 16.4 MPa. [ABSTRACT FROM AUTHOR]

As semiconductor devices become miniaturized, the importance of the molecular-level understanding of the fabrication processes is growing. Titanium nitride (TiN) is an important material utilized in various architectural components of semiconductor devices requiring precise control over size and shape. A reported process for atomic layer etching (ALE) of TiN involves surface oxidation into titanium oxide (TiO2) and selective oxidized layer removal by hydrogen fluoride (HF). However, the chemical selectivity of these Ti-based materials in the etching process by HF remains unclear. In this study, computational chemistry methods utilizing density functional theory (DFT) calculations were applied to the fluorination reactions of TiN, TiO2, and SiO2 to identify and compare the surface chemical reactivity of these substrates toward etching processes. It is shown that the materials can be etched using HF, leaving TiF4 and SiF4 as the byproducts. However, while such a TiN reaction is thermodynamically hindered, the etching of TiO2 and SiO2 is suggested to be favorable. Our study provides theoretical insights into the fluorination reactivity of TiN, which has not been reported previously regardless of technological importance. Furthermore, we explore the etching selectivity between TiN, TiO2, and SiO2, which is a crucial factor in the ALE process conditions of TiN. [ABSTRACT FROM AUTHOR]

Absorption losses and laser-induced damage threshold (LIDT) are considered to be the major constraints for development of optical coatings for high-power laser optics. Such coatings require paramount properties, such as low losses due to optical absorption, high mechanical stability, and enhanced damage resistance, to withstand high-intensity laser pulses. In this work, heterostructures were developed by sub-nanometer thin films of SiO2 and HfO2 using the plasma-enhanced atomic layer deposition (PEALD) technique. Thin-film characterization techniques, such as spectroscopic ellipsometry, spectrophotometry, substrate curvature measurements, X-ray reflectivity, and Fourier transform infrared spectroscopy, were employed for extracting optical constants, residual stress, layer formation, and functional groups present in the heterostructures, respectively. These heterostructures demonstrate tunable refractive index, bandgap, and improved optical losses and LIDT properties. The films were incorporated into antireflection coatings (multilayer stacks and graded-index coatings) and the LIDT was determined at 355 nm wavelength by the R-on-1 method. Optical absorptions at the reported wavelengths were characterized using photothermal common-path interferometry and laser-induced deflection techniques. [ABSTRACT FROM AUTHOR]

In the present work, aluminum matrix composites reinforced with graphene nanoplatelets (GNPs: 0.15-0.45wt.%) and silicon dioxide (SiO2: 1, 3, 6, 9wt.%) were produced by the powder metallurgy method. Hardness, compressive strength, density, friction coefficient, and wear rate of the prepared specimens were examined. According to the experimental results, the best compressive strength (~ 390 MPa), density (~ 2.66 g/cm3), hardness (~ 62 HV), the lowest porosity (~ 1.3%), friction coefficient (~ 0.19 for a load of 10 N), and wear rate (~ 0.003 mm3/Nm for a load of 5 N) were detected et al.-6SiO2-0.15graphene composite. Compared to pure Al, the compressive strength, hardness, and wear resistance of Al-6SiO2-0.15graphene composite were improved by ~ 110%, ~ 106%, and ~ 107, respectively. Hence, it may be concluded that SiO2 has excellent wear resistance and graphene has remarkable strength, good solid lubricating properties for Al-based composites. [ABSTRACT FROM AUTHOR]

With the increase in environmental pollution, studies on the use of sustainable resources are increasing day by day. For this purpose, the use of natural fiber-reinforced polymer composites is encouraged in many areas such as automotive, transportation, construction, and home textiles. However, they are flammable and therefore seriously threaten the safety of people and property. Various flame retardant additives have been used to improve the flame retardancy properties of these composites. In this study, silicon dioxide (SD) and zinc borate (ZB) microparticles in different weight percentages (3, 5, 7, and 10%) were reinforced to give flame retardant properties to jute-epoxy composites. In addition, composites containing both SD and ZB microparticles were produced and they were labeled as HB. Then, thermal conductivity, flammability, water absorption, and mechanical properties of these composites were investigated. The burning rate of the composites decreased as the amount of microparticle increased. 5ZB5SD, including %5 SD and %5 SD microparticles, showed 36.60% less burning rate than the neat jute-epoxy composite. 5ZB showed 10.84% higher tensile strength than the neat juteepoxy. The impact strength of the specimens increased with the increase in the filling ratio, and 5ZB5SD showed approximately 2.50 times the impact strength of the jute-epoxy composite. [ABSTRACT FROM AUTHOR]

The Glass generally have silicon dioxide as their forming oxide, which is accompanied by other metallic oxides that allow them to be brightened, transparent, chemically stable, insoluble in water, and colored. It is the most versatile material invented by man that exists and stands out among other materials because it can be infinitely recycled, allowing the saving of natural resources, energy and costs. It has historically played important roles in architecture, automotive, home furnishings and packaging. Today it is an essential element in key sectors such as energy, biomedicine, agriculture, electronics, telecommunications, optics and aerospace. This work joins the efforts of the United Nations and the international scientific community to declare 2022 "International Year of Glass", a commemoration that celebrates the past, present and future of the most transformative material in the history of humanity. [ABSTRACT FROM AUTHOR]

Rice straw is a waste product from rice manufacturing that contains cellulose (32–47%), hemicellulose (19-27%), lignin (5–24%), and ash (13–20%). The ash form consists of a large percentage of silicon dioxide (SiO2) with widespread use in the industrial field. The extraction of silicon dioxide has been conducted using the sol-gel and ashing method combined with the leaching process using an acid solution such as hydrochloric acid (HCl) at a concentration of 3%. In using HCl with a concentration of 3%, impurities are often found in the SiO2 sample. Therefore, this study uses the leaching method with HCl of several variations (3%, 5%, and 7%). By raising the concentration of HCl in this process, the quality of SiO2 without impurities is increased. The results indicate that increasing the concentration of HCl can significantly lower the sample’s impurity content. In the 3% treatment, impurities were found in the form of Carbon and Calcium. The treatment obtained no impurities using 5% and 7% HCl concentrations. As a result, the highest purity of SiO2 obtained was 89.31% in the 5% HCl treatment. The sample treated with 5% HCl was in the semiconductor region and exhibited an amorphous structure. [ABSTRACT FROM AUTHOR]

At present, agricultural soils are affected by salinity due to the excessive use of synthetic fertilizers and poor quality of the water for agricultural irrigation. Currently, products based on silicon (Si) are being applied to help the sustainability of agriculture, in addition, Si benefits plants to have greater tolerance to pests and diseases, helps against heavy metal toxicity and acts against water and salt stress. Therefore, the aim of the study was to evaluate the effect of silicon as a salinity mitigator on seed germination and initial growth of tomato seedlings. The work was carried out in the Germplasm laboratory of the Autonomous University of Baja California Sur, Mexico. The selected tomato varieties were cherry (Solanum lycopersicum var. Cerasiforme), beef (Solanum lycopersicum var. Floradade) and saladette (Solanum lycopersicum var. Río Grande). The experimental design was completely randomized with a 2 x 3 factorial arrangement, where factor A was saline concentrations (0, 25, 50 mM) of sodium chloride (NaCl) and factor B was silicon dilutions (0, 1, 2 mM). Each treatment included four repetitions of 25 seeds each. Tomato cultivars showed different effects regarding salinity. The cherry cultivar showed decreases in its germinative variables with increasing salinity, indicating that the Floradade and Río Grande cultivars are more tolerant to salinity. In this same sense, silicon presented a protective effect in the interaction (NaCl + Si), showing positive effects by increasing the variables evaluated. [ABSTRACT FROM AUTHOR]

Silica nanoparticles are eco-friendly with high heat transfer potential due to their low-cost synthesis, abundant natural resources, and mass production. Silica nanoparticles with advantages such as biocompatibility, ease-of-functionalization, and large surface area are widely employed in solar applications. Silica nanoparticles possess excellent properties such as good photoconductivity, ideal thermal expansion, high corrosion resistance, and long-term durability, which improve the system's overall efficiency. Dimethyldichlorosilane was employed to prepare silica nanoparticles into hydrophobic nanoparticles. The titration method computed the hydroxyl number of silica nanoparticles and reduced it after modification. The novelty of this work is to enhance the overall efficiency of the solar water heater by adding silica nanoparticles in heat transfer fluid owing to its higher thermal stability, heat resistance and improved structural properties of the nanoparticle. This work reveals a detailed study on the effect of silica nanoparticles on the performance parameters of the solar water heater. Silicon nanoparticles are dispersed with water using NaOH for pH adjustments and Cetyl Triammonium Bromide (CTAB) (1% by wt) as the dispersant to accelerate the vaporization and heating of the medium by local nanoscale heating. This study proposes that incorporating silica nanoparticles at different mass fractions shall improve the s overall efficiency of solar collectors. Silica nanoparticles are dispersed into water with and without using surfactant inside the absorber riser tubes for different mass fractions. The efficiency of the solar flat plate collector is calculated using the ASHRAE method. A collector of the area of 0.5 m2 of 25 LPD has been envisioned and made up with necessities to insert T-type thermocouples to study the temperature distribution. The weight fractions used are 0.2%, 0.4%, and 0.8%, and the experimental results showed an improved heat transfer was pragmatic in the collector using nanoparticles. The efficiency of the solar collector is improved by 2.5, 5.1 and 8.4% by adding Silicon dioxide nanoparticles at 0.2%, 0.4%, and 0.8% weight fractions, respectively. This study concludes that silicon oxide possesses high heat transfer potential and shall be employed in thermal systems. [ABSTRACT FROM AUTHOR]

A reconfigurable Substrate-Integrated Waveguide (SIW) filter operating in the THz region was designed in this work. Two SIW resonators were coupled through a magnetic iris to form a second-order filter with a double-layer substrate. The first substrate was silicon of permittivity 11.9; on top of it, silicon dioxide of permittivity 3.9 was placed. The ground and upper plane were composed of gold plates. Graphene material was then used for the tunability of the filter. A thin graphene sheet was sandwiched between the silicon dioxide substrate and the upper gold plate. An external DC bias voltage was then applied to change the chemical potential of graphene, which, in turn, managed to change the operational center frequency of the filter within the range of 1.289 THz to 1.297 THz, which translated to a bandwidth range of 8 GHz. The second part of this work centered on changing the aspect ratio of the graphene patch to change the center frequency. It was observed that the frequency changed within the range of 1.2908 THz to 1.2929 THz, which gave a bandwidth of 2.1 GHz change. [ABSTRACT FROM AUTHOR]

Silicon is one of the most monitored elements in extractables and leachables studies of pharmaceutical packaging systems and related components. There is a need to review and evaluate toxicological thresholds of silicon because of its direct contact with drug products (DP) especially a liquid form of DP with the widely used pharmaceutical packaging systems made of silicon materials like glass and silicone. It is required by regulatory authorities to test silicon content in DP; however, there are no official guidelines on the toxicology of silicon that are currently available, yet the knowledge of toxicological thresholds of silicon is critical to justify the analytical limit of quantification (LOQ). Therefore, we reviewed the toxicity of silicon to derive a toxicological threshold by literature review of toxicity studies of both inorganic and organic silicon compounds. Oral toxicity is low for inorganic silicon like silicon dioxide or organic silicon polymers such as silicone tube/silicone oil (polydimethylsiloxane, or namely, PDMS as the major ingredient). In comparison, inhalational toxicity of silicon dioxide leads to pulmonary silicosis or even lung cancer. When orally administered, the toxicity of silicon dioxide, glass, polymers, or PDMS oligomers varies depending on their morphology, molecular weight (MW), and degrees of polymerization. PDMS with high MW has minimal toxic symptoms with non-detectable degradation/elimination by both intraperitoneal and subcutaneous administration routes, while exposure to either PDMS or small molecule dimethyl silicone compounds by the intravenous administration route may lead to death. We here determined a general parenteral permitted daily exposure (PDE) of 93 μg/day for inorganic silicon element and 100 μg/day for organic silicon element by reviewing toxicological data of both forms of silicon. In conclusion, this work provides evidence for pharmaceutical companies and regulatory agencies on the PDEs of silicon elements in pharmaceutical packaging and process components through a variety of administration routes. [ABSTRACT FROM AUTHOR]

Pyroptosis is a newly discovered type of programmed cell death associated with inflammatory and fibrotic diseases. Macrophages play an important role in inducing early immune inflammation in systemic sclerosis (SSc). To investigate the effect of macrophages pyroptosis on fibrosis of SSc. Pyroptosis/inflammatory markers in serum and skin of SSc patients were detected. Bleomycin (BLM) was subcutaneously injected to establish SSc mouse model. The levels of pyroptosis markers, dermal thickness and collagen deposition in skin were assessed before and after the administration of pyroptosis inhibitors, including MCC950, Disulfiram and necrosulfonamide (NSA). Human-derived monocyte-macrophage cell line (THP-1) or mouse bone marrow-derived macrophages (BMDMs) were primed with lipopolysaccharide (LPS) and stimulated by silicon dioxide (SiO 2) to induce cell pyroptosis. Fibroblasts from patients with SSc were co-cultured with pyroptotic THP-1 cells, and the collagen production was assessed. Pyroptotic/inflammatory proteins, including NLRP3, cleaved-Caspase (CASP)1, GSDMD-N terminal and IL-18 were increased in the serum, and ASC aggregation and GSDMD were elevated in macrophages in the skin of SSc patients. SSc mice showed increased pyroptosis markers, dermal thickness and collagen deposition in skins, which were alleviated by MCC950, Disulfiram and NSA. Pyroptosis of THP-1 cells and BMDMs was induced by LPS/SiO 2 , and it was reduced by the inhibitors of Cathepsin B, NLRP3, CASP1 and GSDMD. Co-culture with pyroptotic THP-1 cells increased the fibrotic proteins in fibroblasts, which were alleviated by pyroptosis inhibitors. SSc patients and BLM-induced mouse model presented increased pyroptosis. LPS/SiO 2 -induced macrophage pyroptosis promoted fibrosis of SSc through Cathepsin B/NLRP3/GSDMD pathway. • Macrophage pyroptosis was increased in SSc patients and BLM-induced SSc mouse model. • Inhibition of pyroptosis reduced inflammation and fibrosis of SSc mouse model. • Inhibiting NLRP3/GSDMD-mediated macrophage pyroptosis inactivates fibroblasts. [ABSTRACT FROM AUTHOR]

Russia's energy sector that uses coal for heat and electricity generation is a large source of ash and slags, the dumps of which occupy large areas and at the same time pose problems for the environment. These dumps contain, among other components, alumina and other valuable products. In the ash dumps from coal-fired power plants in the Ural region, approximately 350 million t of ash has been accumulated by now, and the amount continues to grow by 7–8 million t per annum. Given the conditions emerging on the world market, the obtaining of alumina from the ash and slag dumps at their own enterprises is a problem of Russia's metallurgical industry that is of utmost importance. Thus, the ashes from large, coal-fired thermal power plants in the Ural region of Russia, including the Troitsk, Reftinsk, Verkhnii Tagil, and other power plants, contain 28–32% of alumina and could become a man-made raw material for producing aluminum, thereby partially substituting the import of bauxites in Russia from foreign countries. The article presents the results of experimental studies aimed at elaborating a technology for extracting high-quality alumina from the alumina-rich ash of coal-fired power plants. The influence of various technological parameters on the target product's obtainment process is studied. At the first stage of this process, which involves partial desiliconization of ash by treating it with alkali solution, enriched alumina concentrate is extracted, which is close to low-grade bauxite raw material in its physicochemical properties. At the technology's second stage, a product with a 97–98% content of Al2O3 is obtained using the method of sintering the alumina concentrate with sodium and calcium carbonates; as a result, the alumina extraction ratio from ash is 88–90%. [ABSTRACT FROM AUTHOR]

The aim of the present study was the electrochemical investigation of the inhibition efficiency of aluminum-tripolyphosphate (ATPP) incorporated in silica (SiO2) and chitosan (Chit) coatings prepared on zinc substrates. Coatings were prepared by dip-coating method. Electrochemical characterization of the coatings was performed by using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves (PDP). Effect of ATPP on Zn was also determined in 0.2g/L Na2SO4 solution and its adsorption on zinc was studied. Results concluded that the ATPP adsorption on Zn obeys Langmuir isotherm. The best corrosion resistance was reached when Zn was protected by SiO2 coating, obtained from a precursor sol containing 10-3 M ATPP. [ABSTRACT FROM AUTHOR]

This work presents the immobilization in situ of commercial lipase from Candida antarctica B (CALB) by the sol–gel technique (xerogel) using silica from rice husk ash (RHA) as a source of silicon. It was used the Ionic Liquid (IL) 1-octyl-3-methylimidazolium bromide (C8MI.Br) as additive. The immobilized derivatives were characterized per SEM, XRD, and per method BET. The enzymatic activity of xerogels was evaluated with different tests, these being the reactional thermal analysis, immobilization yield, and operational and storage stability. The XDR showed that the obtained xerogels have halos in the region between 15 and 35° (2θ) what characterizes it as amorphous materials. The SEM analysis of xerogel shows irregular particles with dimensions less than 20 μm. The immobilized presented an esterification activity (EA) with 263.2 and 213.8 U/g, with and without IL, respectively, higher than the free enzyme (169.6 U/g). The immobilized, with and without IL, presented a significant improvement in the activity performance in relation to free enzyme for the three reactional temperatures (40, 60, and 80 °C) evaluated. The operational stability demonstrated that is possible to use xerogel without ionic liquid for 17 recycles and 21 recycles in IL presence. This methodology allows the preparation of new highly active and selective enzyme catalysts using the rice husk ash as a source of silicon, and the ionic liquid [C8MI]Br as additive. Furthermore, the new materials can provide greater viability in the processes, ensuring longer catalyst life. [ABSTRACT FROM AUTHOR]

This paper presents the results of research on the development of a technology intended to process electric smelting dusts of ilmenite concentrate with the extraction of silicon and titanium and the production of products in the form of their dioxides. Dusts were processed for silicon separation using the ammonium fluoride method. The optimum conditions for the fluorination and sublimation process of silicon compounds from the electric smelting dust of the ilmenite concentrate were determined: a temperature of 260 °С, a 6 h duration, and mass ratio of dust to ammonium bifluoride of 1:0.5 ÷ 0.9. The sublimation degree of silicon compounds was ~84–91%. The sublimation of titanium fluorides from the remaining sinter was carried out at a temperature of 600 ± 10 °C for 2 h, the mass ratio titanium-containing residue: ammonium bifluoride of 1:0.5, and the degree of sublimation of titanium fluorides was 99%. Iron, manganese, and chromium impurities in the sublimation of titanium fluorides sublimate to a rather low degree. Pyrohydrolysis of titanium fluoride sublimes at 600 °C and allows for the conversion of fluorides into titanium dioxide by 99.5% in 4–5 h. Titanium dioxide of rutile modification with 99.8% TiO2 was obtained after hydrochloric acid purification and calcination. A technological scheme for the complex processing of dust from the electric smelting of ilmenite concentrates with the production of silica and titanium dioxide is proposed. [ABSTRACT FROM AUTHOR]

New composite aerogel materials based on sodium lignosulfonates obtained by various delignification methods (sulfite, modified bisulfite) and silica using the sol–gel technology and supercritical fluid processes are synthesized. It is shown that the aerogels based on sulfite lignosulfonate are characterized by a more developed porous structure than the aerogels based on bisulfite lignosulfonate. The pore volume of the aerogels based on sulfite lignosulfonate is 1.4–2.0 cm3/g, which is 1.5–7.0-fold greater when compared to the aerogels based on bisulfite lignosulfonate. The specific surface areas of the aerogels based on sulfite and bisulfite lignosulfonates are 284–452 and 104–280 m2/g, respectively. [ABSTRACT FROM AUTHOR]

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BackgroundLipid metabolism imbalance is tightly linked to the development and progression of multiple diseases. The phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway is important for the regulation of lipid metabolism. However, whether silicosis is associated with lipid metabolic abnormalities has yet to be explored. ObjectiveTo observe the changes of lipid deposition, cholesterol, and phosphorylated proteins of PI3K/AKT/mTOR pathway in silicon dioxide (SiO2)-induced MLE-12 cells and to explore potential mechanism of lipid composition regulated though the pathway. Methods(1) MLE-12 cells were stimulated with 50 mg·L−1 SiO2 suspension, and divided into fourgroups: a control group and three SiO2 groups (12, 24, and 48 h of stimulation). (2) Cellproliferation was detected to determine an optimal dose of LY294002, an inhibitor of PI3K protein. LY294002 at 5 μmol·L−1 was used for further study, in which MLE-12 cells cultured for 48 h were divided into four groups: a control group; a 50 mg·L−1 SiO2 suspension stimulation group; a 50 mg·L−1 SiO2 suspension and 5 μmol·L−1 LY294002 treatment group; a 5 μmol·L−1 LY294002 treatment group. Total cholesterol (TC), free cholesterol (FC), cholesterol ester (CE; total cholesterol minus free cholesterol), and triglycerides (TG) were measured with enzyme assay kits. Lipid deposition was observed using Oil Red O staining. The expressions of p-PI3K, p-AKT, and p-mTOR proteins were detected by Western blotting. Results(1) The contents of TC, FC, and CE in the 50 mg·L−1 SiO2-induced MLE-12 cells were increased compared to those of the control group in a time-dependent manner by trend analysis, and the increment at 24 and 48 h were significant. By 48 h, the contents of cholesterol indicators were all elevated: TC from (2.242±0.181) mg·g−1 to (5.148±0.544) mg·g−1, FC from (1.923±0.158) mg·g−1 to (4.168±0.433) mg·g−1, and CE from (0.318±0.067) mg·g−1 to (0.978±0.134) mg·g−1, compared with the control group (P0.05). The SiO2 suspension induced orange-red particle deposition in the MLE-12 cells, especially at 48 h (P