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Dual-fraction proteomics reveals a novel class of proteins impacted by nanoparticle exposure. Background: Nanoparticles (NPs) interact with cellular proteomes, altering biological processes. Understanding these interactions requires comprehensive analyses beyond solely characterizing the NP corona. Methods: We utilized a dual-fraction mass spectrometry (MS) approach to analyze both NP-bound and unbound proteins in Saccharomyces cerevisiae sp. protein extracts exposed to silica nanoparticles (SiNPs). We identified unique protein signatures for each fraction and quantified protein abundance changes using spectral counts. Results: Strong correlations were observed between protein profiles in each fraction and non-exposed controls, while minimal correlation existed between the fractions themselves. Linear models demonstrated equal contributions from both fractions in predicting control sample abundance. Combining both fractions revealed a larger proteomic response to SiNP exposure compared to single-fraction analysis. We identified 302/56 proteins bound/unbound to SiNPs and an additional 196 "impacted" proteins demonstrably affected by SiNPs. Conclusion: This dual-fraction MS approach provides a more comprehensive understanding of nanoparticle interactions with cellular proteomes. It reveals a novel class of "impacted" proteins, potentially undergoing conformational changes or aggregation due to NP exposure. Further research is needed to elucidate their biological functions and the mechanisms underlying their impact. [ABSTRACT FROM AUTHOR]

Crystalline silica is a Group I lung carcinogen primarily known as a causative agent for silicosis. A study was performed to quantify respirable dust, and respirable crystalline silica (RCS) in the rice mills of northeast India. Seventy-two respirable dust samples were collected from the worker's breathing zone from four rice mills at three locations: feeding, sieving, and polishing sections for two paddy varieties: Ranjit and Sali. The National Institute of Occupational Safety and Health (NIOSH), method #7602, was used to determine RCS. The results show that geometric mean TWA dust and RCS emissions in the rice mills varied from 3.97 to 455.00 mg/m3 and 0.02 to 5.38 mg/m3, respectively. RCS exposures were higher during milling of the Sali variety paddy (GM: 0.76 mg/m3) than the Ranjit variety paddy (GM: 0.25 mg/m3). Respirable dust and RCS emissions were considerably higher in the feeding and sieving sections than in the polishing section. Respirable dust and RCS exposure varied significantly (p < 0.001) with paddy variety. Respirable dust and RCS were highly correlated for different rice mills; however, the proportion of RCS in the dust was higher in the Sali variety paddy than in the Ranjit variety paddy. RCS exposure to the workers at the feeding and sieving sections was observed to be higher than the occupational exposure limits (OELs) published by Safe Work Australia, American Conference of Governmental Industrial Hygienists (ACGIH), National Institute for Occupational Safety and Health (NIOSH), Health and Safety Executive (HSE), and Factories Amendment Act, 1987, Government of India. [ABSTRACT FROM AUTHOR]

Natural disasters such as landslides are frequent occurrences around the world. Despite the many studies conducted on slope behavior, the loss of countless lives and valuable property continues. This study employed the Limit Equilibrium Method (LEM), simulated using SLOPE/W software, based on the Mohr-Coulomb failure criterion to examine the behavior of a silica sand slope under surcharge load. The properties of silica sand, such as dry unit weight (γd), saturated unit weight (γsat), angle of internal friction (φ), and soil cohesion (c), were determined through compaction and consolidated-drained (CD) triaxial tests. The computed Factor of Safety (FOS) value from the SLOPE/W analysis is 0.955 at an applied surcharge load of 6.4 kPa. The result was then compared with Finite Element Method (FEM), simulated using Plaxis 3D software based on Strength Reduction Method under the same loading conditions. The results from both analyses showed that the Plaxis 3D analysis generally gave a higher FOS value (6.321) compared to the FOS value obtained from the SLOPE/W analysis (0.955). The shape and critical slip surface are almost identical for each analysis. The results of both numerical simulations were then compared to the experimental testing. The LEM method provides a more realistic indication of FOS. A clear understanding of the approach employed in the LEM and FEM analyses determines the validity of the analysis carried out. [ABSTRACT FROM AUTHOR]

This study explores the application of machine learning techniques, specifically principal component analysis (PCA), to analyze the influence of silica content on the physical and chemical properties of aerogels. Silica aerogels are renowned for their exceptional properties, including high porosity, large surface area, and low thermal conductivity, but their mechanical brittleness poses significant challenges. The study initially utilized cross-correlation analysis to examine the relationships between key properties such as the Brunauer–Emmett–Teller (BET) surface area, pore volume, density, and thermal conductivity. However, weak correlations prompted the application of PCA to uncover deeper insights into the data. The PCA results demonstrated that silica content has a significant impact on aerogel properties, with the first principal component (PC1) showing a strong positive correlation (R2 = 94%) with silica content. This suggests that higher silica levels correspond to lower thermal conductivity, porosity, and BET surface area, while increasing the density and elastic modulus. Additionally, the analysis identified the critical role of thermal conductivity in the second principal component (PC2), particularly in samples with moderate to high silica content. Overall, this study highlights the effectiveness of machine learning techniques like PCA in optimizing and understanding the complex inter-relationships among the physio-chemical properties of silica aerogels. [ABSTRACT FROM AUTHOR]

ABSTRACT Respirable crystalline silica (RCS) poses significant health risks in workplaces, including underground coal mines, metal and nonmetal mining, construction sites, fire suppression, and oil and gas industries. Raman spectroscopy offers a promising avenue for direct analysis of RCS on sample filters with minimal pretreatment. However, the presence of organic compounds (OC) in the samples can generate fluorescence signals that interfere with RCS measurements, potentially saturating the detector even at short integration times, particularly when using portable Raman instruments. This study explores a novel approach to address these challenges by functionalizing filters with a hydroxyapatite/silver bromide/titanium dioxide (HAT) photocatalyst, facilitating the oxidation and removal of OC using the Raman excitation laser. Photocatalytic degradation experiments conducted on polyvinyl chloride (PVC) filters preloaded with HAT and anatase titanium dioxide (TiO2) particles demonstrated that HAT significantly enhances the degradation of OC, such as oxalic acid, under visible light irradiation compared to TiO2. Additionally, fluorescence interferences were reduced for coal dust samples analyzed on functionalized silver filters using a portable Raman instrument. The efficacy of HAT in OC photocatalytic degradation on silver filters was further confirmed using a benchtop micro‐Raman system. Filter functionalization had minimal impact on filtration efficiencies and pressure drops, indicating the feasibility of this approach for improving RCS analysis while maintaining filter performance. [ABSTRACT FROM AUTHOR]

Direct-on-Filter (DoF) analysis of respirable crystalline silica (RCS) by Fourier Transform Infrared (FTIR) spectroscopy is a useful tool for assessing exposure risks. With the RCS exposure limits becoming lower, it is important to characterize and reduce measurement uncertainties. This study systematically evaluated two filter types (i.e., polyvinyl chloride [PVC] and polytetrafluoroethylene [PTFE]) for RCS measurements by DoF FTIR spectroscopy, including the filter-to-filter and day-to-day variability of blank filter FTIR reference spectra, particle deposition patterns, filtration efficiencies, and pressure drops. For PVC filters sampled at a flow rate of 2.5 L/min for 8 h, the RCS limit of detection (LOD) was 7.4 μg/m3 when a designated laboratory reference filter was used to correct the absorption by the filter media. When the spectrum of the pre-sample filter (blank filter before dust sampling) was used for correction, the LOD could be up to 5.9 μg/m3. The PVC absorption increased linearly with reference filter mass, providing a means to correct the absorption differences between the pre-sample and reference filters. For PTFE, the LODs were 12 and 1.2 μg/m3 when a designated laboratory blank or the pre-sample filter spectrum was used for blank correction, respectively, indicating that using the pre-sample blank spectrum will reduce RCS quantification uncertainty. Both filter types exhibited a consistent radially symmetric deposition pattern when particles were collected using 3-piece cassettes, indicating that RCS can be quantified from a single measurement at the filter center. The most penetrating aerodynamic diameters were around 0.1 µm with filtration efficiencies ≥ 98.8% across the measured particle size range with low-pressure drops (0.2–0.3 kPa) at a flow rate of 2.5 L/min. This study concludes that either the PVC or the PTFE filters are suitable for RCS analysis by DoF FTIR, but proper methods are needed to account for the variability of blank absorption among different filters. [ABSTRACT FROM AUTHOR]

As the role of exosomes in physiological and pathological processes has been properly perceived, harvesting them and their internal components is critical for subsequent applications. This study is a debut of intermittent lysis, which has been integrated into a simple and easy-to-operate procedure on a single paper-based device to extract exosomal nucleic acid biomarkers for downstream analysis. Exosomes from biological samples were captured by anti-CD63-modified papers before being intermittently lysed by high-temperature, short-time treatment with double-distilled water to release their internal components. Exosomal nucleic acids were finally adsorbed by sol–gel silica for downstream analysis. Empirical trials not only revealed that sporadically dropping 95 °C ddH2O onto the anti-CD63-modified papers every 5 min for 6 times optimized the exosomal nucleic acids extracted by the anti-CD63 paper but also verified that the whole deployed procedure is applicable for point-of-care testing (POCT) in low-resource areas and for both in vitro (culture media) and in vivo (plasma and chronic lesion) samples. Importantly, downstream analysis of exosomal miR-21 extracted by the paper-based procedure integrated with this novel technique discovered that the content of exosomal miR-21 in chronic lesions related to their stages and the levels of exosomal carcinoembryonic antigen originated from colorectal cancer cells correlated to their exosomal miR-21. [ABSTRACT FROM AUTHOR]

TLC (thin-layer chromatography) and HPTLC (high-performance thin-layer chromatography) in normal (NP) and reversed (RP) phase systems were combined with densitometry to analyze caffeine, propyphenazone, and paracetamol. This work aims to check whether comparable limit of detection (LOD) values can be obtained on TLC and HPTLC plates. Analyses were performed on five (NP) or four (RP) different stationary phases (chromatographic plates), testing, in both cases, three mobile phases. It is shown that by using both TLC and HPTLC plates, it is possible to develop chromatographic conditions that enable the detection of compounds analyzed in amounts ranging from a dozen to several dozen µg/spot. In the RP system, lower LOD values for all tested compounds were obtained using TLC than HPTLC. However, performing analyses in the NP, similar (of the same order) LOD values were obtained for caffeine, propyphenazone, and paracetamol when using both TLC and HPTLC plates. For example, during the NP-HPTLC analysis using silica gel 60F254 plates (#1.05548) and mobile phase B (n-hexane—acetone—ammonia, 25:25:0.5, v/v/v), LOD values for caffeine, propyphenazone, and paracetamol were 0.010, 0.046, and 0.030 μg/spot, respectively. During NP-TLC analysis using silica gel 60F254 (#1.05554 plates) and the mobile phase C (chloroform—toluene—ethyl acetate—methanol—80% acetic acid, 18:18:7.5:6:0.3, v/v), the values of LOD were 0.054, 0.029, and 0.016 μg/spot, respectively. During RP-TLC analysis using TLC RP-18F254 plates (#1.05559) and mobile phase F (methanol-water, 40:10, v/v), the LOD values were 0.019, 0.024, and 0.053 μg/spot, respectively. Therefore, for economical reasons, TLC plates should be recommended for analyses of caffeine, propyphenazone, and paracetamol, which are several times cheaper than HPTLC plates. [ABSTRACT FROM AUTHOR]

Personal air monitoring using a TSI SidePak AM520 personal aerosol monitor was performed on a northern Colorado construction site during five tasks from the OSHA Table 1 : Specified Exposure Control Methods When Working With Materials Containing Crystalline Silica to estimate silica dust concentrations in real time. Photometric measurements were modified using a gravimetric correction factor and a % respirable crystalline silica adjustment. Each task was sampled once; sample time ranged from 14 min to 40 min, with a mean sample time of 27 min. The mean silica dust concentration estimates (μg/m3) (standard deviation [SD]) for the five tasks computed from the TSI SidePak AM520 respirable dust measurements were core drilling 12 μg/m3 [2.46], grinding 918 μg/m3 [1134.08], cutting with a walk-behind saw 36 μg/m3 [79.67], jackhammering 27 μg/m3 [23.24], and dowel drilling 66 μg/m3 [77.65]. Silica exposure estimates from real-time monitoring can be used to identify exposures that may be related to inadequate controls or worker behaviors that contribute to peak exposures. Respirable crystalline silica exposure estimates presented here are likely not generalizable to other construction sites or tasks. [ABSTRACT FROM AUTHOR]

Objectives Since the 1920s, Zambia's mining sector has experienced growth, which has increased the number of mine workers employed in the industry. Consequently, the potential for occupational exposure and prevalence of occupational diseases have also increased. Unfortunately, Zambia does not currently have legislative guidelines for workplace air monitoring and compliance. This study's objectives were to evaluate copper miners' personal exposure to respirable dust and respirable crystalline silica (RCS) and to assess workplace compliance using the European Standard for workplace air monitoring and measurement (EN689:2018). Methods This cross-sectional study collected 100 personal respirable dust exposure samples at a Zambian copper mine in 2023. These samples were weighed using NIOSH method 0600 and analyzed for crystalline silica using Fourier transform infrared spectroscopy (KBr pellet) (NIOSH method 7602). Additionally, 253 respirable dust exposure measurements collected at the mine between 2017 and 2022 were included for comparison. Results The median respirable dust exposure for the 2023 exposure measurements was 0.200 mg/m3 (95th percentile 2.871 mg/m3) compared to 0.400 mg/m3 (95th percentile 3.050 mg/m3) for the historic data. The median RCS exposure was 0.012 mg/m3 (95th percentile 0.163 mg/m3). Using EN689:2018, it was found that from 15 work areas, only six work areas complied with the standard for respirable dust exposure and only seven work areas complied with the standard for RCS exposure. Conclusions At the mining site, several work areas had substantial exposure to respirable dust and RCS. Therefore, management needs to prioritize these areas when implementing control measures to reduce dust exposure. For the Zambia mining industry to manage exposure to respirable dust and RCS, it is necessary to implement standardized monitoring strategies. This study has demonstrated that EN689:2018 can be used successfully to determine compliance among Zambian mining work areas. [ABSTRACT FROM AUTHOR]

There is a significant silicosis risk for workers fabricating engineered stone (ES) products containing crystalline silica. The aims of this study by SafeWork NSW were to: (i) assess current worker exposure to respirable dust (RD) and respirable crystalline silica (RCS) following a 5-y awareness and compliance program of inspections in ES workshops and (ii) to identify improvements in work practices from the available evidence base to further reduce exposures. One hundred and twenty-three personal full shift samples taken on as many workers and 34 static samples across 27 workshops fabricating ES were included in the final assessment. The exposure assessment was conducted using Casella Higgins–Dewell cyclones (Casella TSI) placed in the breathing zone of workers attached to SKC Air Check XR 5000 or SKC Chek TOUCH sampling pumps. Sample filters were sent to an ISO (2017) 17025:2017 accredited laboratory for gravimetric analysis for RD and X-Ray Diffraction (XRD) analysis to determine the amount of deposited RCS i.e. alpha-quartz and cristobalite. All workshops used wet methods of fabrication. The geometric mean (GM) of the pooled result for respirable dust (RD) was 0.09 mg/m3 TWA-8 h and 0.034 mg/m3 TWA-8 h for RCS. The highest exposed workers with a GM RCS of 0.062 mg/m3 TWA-8 h were those using pneumatic hand tools for cutting or grinding combined with polishing tasks. Workers operating semiautomated routers and edge polishers had the lowest GM RCS exposures of 0.022 mg/m3 TWA-8 h and 0.018 mg/m3 TWA-8 h respectively. Although ES workers remain exposed to RCS above the workplace exposure limit (WEL) of 0.05 mg/m 3 TWA-8 h, these results point to a very substantial reduction in exposures compared to poorly controlled dry methods of fabrication. Therefore, the wearing of respiratory protection by workers remains necessary until further control measures are more widely adopted across the entire industry e.g. reduction in the crystalline silica content of ES. [ABSTRACT FROM AUTHOR]

Breast cancer (BRCA) is the most common malignancies worldwide with increasing rate. Dolichol phosphate mannose synthase (DPMS) is a critical mannosyltransferase involved in the posttranslational modification of proteins. At present, there is limited knowledge regarding the function of DPMS in breast cancer. In this study, silica analysis in multiple datasets found that dolichyl‐phosphate mannosyltransferase subunit 2 (DPM2) is an unfavorable prognostic marker, suggesting its oncogenic role. Cell counting kit‐8 and apoptosis assays show that DPM2‐silenced cancer cells exhibit decreased growth potential and enhanced cell death rate. Further, transwell and wound healing assays show reduced invasion and migration capabilities in DPM2 knockdown groups, xenograft nude mice model demonstrated smaller tumor volume in DPM2 silenced BC cells. Then, the underlying downstream mechanism of DPM2 in BC was predicted and analyzed, highlighting classical tumorigenic pathways like JAK/STAT signaling pathway and oxidative phosphorylation activated in the cancer group. Finally, ChIP‐seq analysis, expression correlation analysis, inhibitor treatment, and dual luciferase assays show that DPM2 is transcriptionally activated by estrogen receptor1 (ESR1). The results show that high expression of DPM2 mRNA is significantly correlated with shorter overall survival (OS) and disease‐free survival (DFS) in breast cancer patients, and in vitro knockdown of DPM2 can significantly inhibit the malignant phenotypes of cells, including proliferation, invasion, migration, and apoptosis. These results suggest that DPM2 may play an important role in breast cancer. Altogether, we first uncovered the tumorigenic and prognostic role of DPM2 in breast cancer, cellular assays, and bioinformatics analysis highlighted DPM2 as oncogene via inhibited cancer‐related signaling pathways in breast cancer. Besides, DPM2 is transcriptionally activated by ESR1, the signaling axis of ESR1/DPM2 provides a new strategy for BC‐targeted therapy. [ABSTRACT FROM AUTHOR]

Background Globally, the number of small-scale miners (SSM) is estimated to be more than 25 million, but it supports the livelihoods of around 100 million individuals. In Tanzania, the number of SSM has increased from an estimated 150,000 in 1987 to ~1.5 million in 2017. The miners are at a high risk of occupational-related health challenges. The study aimed to assess the concentrations of respirable crystalline silica (RCS) and radon among the tanzanite mining communities in Simanjiro District, Tanzania. Methods We carried out a cross-sectional study involving the Mererani mines in Tanzania. These are underground mines comprised of informally employed miners, i.e. SSM. Concentrations of RCS and radon gas were measured in 44 study units, i.e. 22 mining pits and within 22 houses in the general community, e.g. shops in the peri-mining community. A total of 132 respirable personal dust exposure samples (PDS), 3 from each of the study units were taken, but only 66 PDS from the mining pits were analysed, as this was the main interest of this study. Radon concentration was measured by continuous monitoring throughout the working shift (and overnight for residences) using AlphaGuard monitor. The medians and comparison to the reference values, OSHA USA PEL and WHO/IARC references, were done for RCS and radon, respectively, using SPSS Ver. 27.0.0). Results The median time-weighted average (TWA) concentration of the RCS in the mining pits was 1.23 mg/m3. Of all 66 personal dust samples from the mining pits, 65 (98.5%) had concentrations of RCS above the Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) of 0.05 mg/m3. Mining pits had a median radon concentration of 169.50 bq/m3, which is above the World Health Organization (WHO)/International Commission on Radiation Protection (ICRP) recommended reference of 100.00 bq/m3 but not above the upper reference of 300.00 bq/m3, while the community buildings had a median radon concentration of 88.00 bq/m3. Overall, 9 (20.5%) and 17 (38.6%) radon measurements were above 300.00 bq/m3 and between 100.00 and 300.00 bq/m3 references, respectively. Specifically, in the mining pits, 9 (40.9%) test results were above 300.00 bq/m3, while none of the test results in the community was above 300.00 bq/m3. Conclusion The tanzanite SSM in Mererani we highly exposed to RCS, which increases the risk of pulmonary diseases, including silicosis, tuberculosis, and pulmonary malignancies. Immediate action by OSHA Tanzania should be enforcement of wearing respirators by all miners throughout the working hours. Health education programmes to the SSM must be strengthened and OSHA Tanzania should adopt the 0.05 mg/m3 PEL, and enforce other occupational health and safety measures, including regular use of dust suppression mechanisms (water spray and wet drilling) and monitoring of RCS exposures among SSM. Monitoring of radon exposure both in the mining pits and community buildings should be conducted, and mitigation measures should be implemented in areas that exceed the reference level of 100.00 bq/m3. [ABSTRACT FROM AUTHOR]

Disordered solids exhibit intermittent avalanches when slowly driven by an external load. These avalanches are associated with plastic rearrangements of the atoms at the nanoscale that manifest as stress and energy drops in the loading curve. The complexity arising from their interactions through long‐range elastic fields and the disorder makes statistical approaches suitable for studying their behavior by considering yielding and fracture as a phase transition. To investigate the avalanche statistics, we perform nanoscale simulations using the athermal quasistatic deformation protocol to induce fracture to silica glass samples, which were simulated using the melting‐quenching technique. We identify and measure the avalanches and voids and investigate their evolution in the process of fracture. Our results confirm that the avalanches exhibit scale‐free power law statistics, indicative of a critical phenomenon. [ABSTRACT FROM AUTHOR]

Thermal conductivity is the only measurable parameter for a simple and restricted steady-state apparatus. To deeply explore monolithic silica aerogel's thermophysical properties, not limited to thermal conductivity, we developed a novel differentiable learning (DL) method to evaluate unsteady-state thermal insulation performance by inverse analyzing the hot surface temperature response. In this paper, the monolithic silica aerogel's temperature of hot surface is measured with limited probes, and then the thermal conductivity is obtained by Fourier's law at the steady state and small temperature differences (< 20 K). Further, the specific heat capacity is inversely deduced from the unsteady-state hot surface temperature at large temperature differences (> 100 K) through the inverse analysis of the Levenberg–Marquardt (LM) and DL methods. Herein, DL's predicted accuracy reaches the required measurement precision and keeps consistent with the LM's, but it improves 2–3 orders of magnitude in terms of computational speed, preferably adapted to the limited steady-state experimental method. The DL method is a potentially more powerful data-driven tool for inverse analysis and can be applied to complex circumstances, such as phase transition or erosion material. [ABSTRACT FROM AUTHOR]

Objective(s): Electrospun nanofibrous mats of Polycaprolactone (PCL) and amino modified SBA-15 containing Captopril were prepared and release of drug from prepared nanofibers were investigated in this study. Materials and Methods: Amino modified SBA-15 synthesized through grafting with aminopropyl triethoxy silane. Then, Captopril which is used as an Angiotensin-Converting Enzyme (ACE) inhibitor was loaded as a model drug into the synthesized particles. Furthermore, silica particles containing different amounts of captopril (7.5, 10, 15 mg) were loaded into PCL nanofibers’ structure using electrospinning. Therefore, captopril’s release rate in phosphate buffer was analyzed. The analysis of captopril-loaded silica and captoprilloaded nanofibers (without silica) was done in vitro matrix. To identify the acquired nanofibers, FTIR, SEM, SEM mapping, EDX and average diameter calculation were performed. Results: Comparison between the drug release rate of silica-containing nanofibers and bare silica particles indicated that silica particles positively affected the drug release rate. Moreover, kinetic studies have revealed that the drug release rate follows Higuchi and Korsmeyer-Peppas model. Bare nanofibers’ average diameter was 209 nm while silica and captopril containing nanofibers were 286 nm in average diameter. Conclusion: Therefore, it was concluded that drug-loaded Polycaprolactone nanofibers are potential candidates for biomedical applications. [ABSTRACT FROM AUTHOR]

At the turn of the millennium, the monolithic columns invoked new chances in HPLC. Even more than their organic polymer‐based siblings, the inorganic silica‐based monoliths targeted the territory of classical fully porous particle‐packed columns, promising many benefits. Based on the number of published articles, the monoliths attracted academics just in the first few years after their introduction to the market. Lately, as superficially porous particles and sub‐2‐micron fully porous particles dominated the market, they stayed in the focus of routine laboratories and those who really appreciated the high porosity of the monolithic bed. The monoliths' practical benefits cannot be easily traced in the literature when they gradually lose academics' interest. Nevertheless, after more than 20 years of our experience, we still favor silica monoliths for their low back pressure and longevity when analyzing samples of clinical, pharmaceutical, and environmental origin. At the same time, the high permeability of monoliths enabled the birth of sequential injection chromatography, the medium‐pressure separation technique based on the flexible flow manifold. This minireview aims to check, discuss, and summarize the practical aspects of monolithic silica columns in HPLC and medium‐pressure sequential injection chromatography (SIC) that may not be visible at first sight but are evident retrospectively. [ABSTRACT FROM AUTHOR]

Silica aerogel is a nano-porous ultra-light weight aggregate, and its excellent thermal insulation performance has attracted much attention in building energy conservation. However, the hygrothermal properties parameters such as thermal conductivity, water absorption characteristics, moisture distribution, and pore structure of aerogel incorporated cementitious composites (AICs) are unclear and lack for experimental data. The effects of different aerogel contents on the microstructure and thermophysical parameters of cementitious composites were systematically studied based on traditional characterization methods (Fourier transform infrared, scanning electron microscope) and low field NMR technology was used to study the distribution and migration of water of AICs in the pore structure. The result shows that the microstructure, thermal insulation performance, and hydrophobicity of AICs are affected by aerogel content enormously. The water migration in the pore structure of AICs can be divided into four stages: rapid rise stage (0–15 min), slow growth stage (15 min − 1 h), uniform growth stage (1 – 12 h), and stable stage (12 − 24 h). The thermal conductivity decreases significantly (52.72%) with the increase in aerogel. However, the thermal conductivity of AICs increases after seven days of water absorption. [ABSTRACT FROM AUTHOR]

In nanotechnology, the size and shape control of nanoparticles is crucial as their properties are highly dependent on their morphology. This obliges researchers to work on obtaining uniform size and shape distribution in synthesized particles so that their electrical, optical, and magnetic properties remain uniform within the same batch. This brings the problem of how to quantify the shape and size of nanoparticles in the most accurate way. The most common way to determine size distribution is using UV-vis spectrometry; however, this method disregards the existence of agglomerated particles and may sometimes give an incorrect measurement. Therefore a technique that can obtain this data directly from the transmission electron microscopy (TEM) images of particles would be more reliable as it would capture data for every single particle in the batch. In a classical statistical sense, our interest is the shape and size distribution of nanoparticles. In this paper, we quantify the size and shape of nanoparticles using the statistical techniques applied on TEM images of particles: Functional Data and Shape Analysis. By using this shape theory we obtain the geodesic distances not only between the particles but also among the frames. We further cluster the nanoparticles in terms of their similarities. We want to emphasize the importance of the deformation and how it is done of one nanoparticle onto another. [ABSTRACT FROM AUTHOR]

Composites of the pristine or hydridesilylated nanosilica with caffeic acid (CA) were obtained either by deposition of CA onto the surface of the corresponding silica from excess ethanol solution, or by sorptive modification of silica with ethanol CA solution under fluidized bed conditions, or by mechanical powder mixing. SEM studies revealed that CA–silica composites are composed of tens-micron-size agglomerates/particles comprising of or covered with the network of nanoparticles. FTIR spectroscopic studies confirmed the presence of ≡SiH groups (2255 cm−1) on the surface of hydride-silica in its composites with caffeic acid, and it was found that at low concentration (23 mg/g) CA is present on the nanosilicas' surface mainly in the form of monomers and dimers, while at higher concentration (153 mg/g)—mainly in the form of dimers and probably associates; in all cases surface silanols being involved in interaction with CA molecules. The data on thermogravimetric analysis suggest that silica surface affects the mechanism (and in the case of hydridesilylated silica also the kinetics) of CA thermal degradation. It has been shown that hydridesilylation of nanosilica surface and further its sorptive modification with caffeic acid under fluidized bed conditions allows one to obtain redox-active materials without significant impact on the carrier's structural characteristics (specific surface area). Upon this, caffeic acid deposited onto the nanosilica surface does not loose its antioxidant properties, and hydridesilylated nanosilica has shown the viability of its use as a component of a complex antioxidant. [ABSTRACT FROM AUTHOR]

A novel material, Tris coated magnetic nano structured adsorbent (T-MNSA) was synthesized using incipient wetness impregnation method for removal of bisphenol A (BPA). T-MNSA maximum adsorption capacity was 160 mg/g and sorption density was 0.078 mole BPA/mole of Tris. In addition, degradation using ultrasound assisted bismuth ferrite (BF) sono-catalyst was studied for removal and cost efficiency differences. The degradation results show a complete removal of BPA at condition of 0.10 g/l of BF, 100% power, and 72 kHz frequency. The mechanism study reveals that T-MNSA forms biomolecules and covalently attaches to BPA, but BF generates large amount of H2O2 molecules and breaks down BPA to non-toxic CO2 and water. Cost analysis study reveals that T-MNSA is more economical than BF due to lower production and removal cost, almost ten times lower than degradation process using BF, and the material can be commercially produced in bulk quantities. [ABSTRACT FROM AUTHOR]

(g) FZD5 was measured in hpRPE cells undergoing UOS treated with 100 nM NPD1 or 100 ng/ml Box5 in the presence or absence of 50 ng/ml Wnt5a. (b, c) Quantification of cRel (b) and Wnt5a (C) mRNA by the means of SYBR green-based real-time PCR in hpRPE cells undergoing UOS, ± NPD1. (e-g) In vivo monitoring of p65 nuclear translocation in resting hRPE cells or undergoing UOS cells and exposed to Wnt5a. [Extracted from the article]

Near‐infrared (NIR) diffuse reflection spectroscopy combined with solid‐state 29Si‐nuclear magnetic resonance (NMR) was applied to surface‐methylated silica nanoparticles for rapid determination of the degree of modification of silanol group. 29Si‐NMR with direct polarization method was employed to quantify the amounts of methyl and silanol groups from the areas of the T2, T3, Q2, and Q3 sites for referential samples modified with different amounts of trimethoxymethylsilane (TMMS). The degree of modification obtained by NMR was correlated with the corresponding NIR spectra by partial least squares (PLS) regression, where CH overtone and combination bands of the methyl group played a key role. Validity of the regression model was demonstrated for the mixtures of modified and unmodified samples at different ratios and for the samples prepared using excess amount of TMMS. This protocol will enable a high‐throughput characterization of surface‐modified silica nanoparticles used as a filler for polymer composites and a nucleating agent for polymer foams. [ABSTRACT FROM AUTHOR]

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In this study, we systematically characterized the airborne dust generated from grinding engineered and natural stone products using a laboratory testing system designed and operated to collect representative respirable dust samples. Four stone samples tested included two engineered stones consisting of crystalline silica in a polyester resin matrix (formulations differed with Stones A having up to 90wt% crystalline silica and Stone B up to 50wt% crystalline silica), an engineered stone consisting of recycled glass in a cement matrix (Stone C), and a granite. Aerosol samples were collected by respirable dust samplers, total dust samplers, and a Micro-Orifice Uniform Deposit Impactor. Aerosol samples were analyzed by gravimetric analysis and x-ray diffraction to determine dust generation rates, crystalline silica generation rates, and crystalline silica content. Additionally, bulk dust settled on the floor of the testing system was analyzed for crystalline silica content. Real-time particle size distributions were measured using an Aerodynamic Particle Sizer. All stone types generated similar trimodal lognormal number-weighted particle size distributions during grinding with the most prominent mode at an aerodynamic diameter of about 2.0-2.3 μm, suggesting dust formation from grinding different stones is similar. Bulk dust from Stone C contained no crystalline silica. Bulk dust from Stone A, Stone B, and granite contained 60, 23, and 30wt% crystalline silica, respectively. In Stones A and B, the cristobalite form of crystalline silica was more plentiful than the quartz form. Only the quartz form was detected in granite. The bulk dust, respirable dust, and total dust for each stone had comparable amounts of crystalline silica, suggesting that crystalline silica content in the bulk dust could be representative of that in respirable dust generated during grinding. Granite generated more dust per unit volume of material removed than the engineered stones, which all had similar normalized dust generation rates. Stone A had the highest normalized generation rates of crystalline silica, followed by granite, Stone B, and Stone C (no crystalline silica), which likely leads to the same trend of respirable crystalline silica (RCS) exposure when working with these different stones. Manufacturing and adoption of engineered stone products with formulations such as Stone B or Stone C could potentially lower or eliminate RCS exposure risks. Combining all the effects of dust generation rate, size-dependent silica content, and respirable fraction, the highest normalized generation rate of RCS consistently occurs at 3.2-5.6 µm for all the stones containing crystalline silica. Therefore, removing particles in this size range near the generation sources should be prioritized when developing engineering control measures. [ABSTRACT FROM AUTHOR]

Microbubbles are small gas-filled bubbles which have wide application in various industries. The stability of microbubble is of primary concern for the application of microbubble. In this research, the stability of microbubble dispersion generated using CTAB surfactant is analyzed by drainage mechanism. The stability of microbubble dispersion is studied on the basis of the half-life of microbubble dispersion. Microbubble dispersion gas fraction and apparent rise velocity of interface of microbubble dispersion are also calculated. The size of microbubble is estimated from the apparent rise velocity of interface of microbubble dispersion. Further, silica nano-particles are added to the surfactants to study their effect on the stability of microbubble dispersion. The observed results clearly indicate that the stability of microbubble dispersion is significantly affected by the surfactant concentration and the weight of silica nano-particle in the liquid. Similar results were observed for the apparent rise velocity of interface and bubble size of dispersion. The present work may be beneficial for the application of microbubble in various chemical and biochemical industries and scientific community. [ABSTRACT FROM AUTHOR]

Background: Congenital hypothyroidism due to defects in iodotyrosine deiodinase has variable phenotypes and can present as hypothyroid or with normal thyroid testing. Methods: Whole exome sequencing was performed in individuals from two families originating from different regions of Sudan. Mass spectrometry of urine and serum iodotyrosines was performed on subjects from both families. Results: A novel iodotyrosine deiodinase (IYD) mutation (c.835C>T; R279C) was identified in individuals from two Sudanese families inherited as autosomal recessive. The mutation was identified by multiple in silica analyses to likely be detrimental. Serum and urine monoiodotyrosine (MIT) and diiodotyrosine (DIT) were markedly elevated in the homozygous subjects. Conclusion: Measurement of serum and urine DIT and MIT was more sensitive than that of urine iodine or serum thyroid function tests to determine the effect of the IYD mutation. [ABSTRACT FROM AUTHOR]

Ambient pressure drying (APD) can prospectively reduce the costs of aerogel fabrication and processing. APD relies solely on preventing shrinkage or making it reversible. The latter, i.e., the aerogel re-expansion after drying (so-called springback effect—SBE), needs to be controlled for reproducible aerogel fabrication by APD. This can be achieved by an appropriate surface functionalization of aerogel materials (e.g., SiO2). This work addresses the fabrication of monolithic SiO2 aerogels and xerogels by APD. The effect of several silylation agents, i.e., trimethylchlorosilane, triethylchlorosilane, and hexamethyldisilazane on the SBE is studied in detail, applying several complementary experimental techniques, allowing the evaluation of the macroscopic and microscopic morphology as well as the composition of SiO2 aerogels. Here, we show that some physical properties, e.g., the bulk density, the macroscopic structure, and pore sizes/volumes, were significantly affected by the re-expansion. However, silylation did not necessarily lead to full re-expansion. Therefore, similarities in the molecular composition could not be equated to similarities in the SBE. The influences of steric hindrance and reactivity are discussed. The impact of silylation is crucial in tailoring the SBE and, as a result, the APD of monolithic aerogels. [ABSTRACT FROM AUTHOR]

Functionalization of mesoporous silica foam (MSF) is a feasible strategy to enhance the electrocatalytic performance of designed sensors. Herein, an organic ligand, pyrene-1-carboxaldehyde hydrazone (PCH), is used to functionalize MSF and as a modifier for carbon paste electrodes to construct a Cu2+ detection sensor. The experimental results demonstrate that the PCH functionalization can significantly enhance the sensor's sensitivity and selectivity. Under optimized conditions, the linear range of the prepared electrochemical sensor are 0.0050–1.0 μM and 1.0–10 μM, and the Cu2+ detection limit is 0.0020 μM. The developed sensor is applied to detect Cu2+ content in standard rice control samples, and the obtained results fall well within the range of marked values. Moreover, the recoveries of the standard addition method are 98.4–102.6 %, suggesting the developed sensor's good accuracy and practicability. • An organic ligand functionalized mesoporous silica foam material was prepared and used to construct Cu2+ sensor. • The highly sensitive and selective of sensor were derived from a novel organic ligand pyrene-1-carboxaldehyde hydrazone. • The accurate results were obtained in the real samples analysis demonstrated the practicability of the prepared sensor. [ABSTRACT FROM AUTHOR]

The deformation of the interfaces between a soft material and hard material in contact plays an important role in the friction and lubrication between them. We recently reported that the elastic property of the contact interface dominated the friction of the interface between a flat polymer hydrogel [double network (DN) gel of 2-acrylamide-2-methylpropanesulfonic acid and N,N-dimethylacrylamide] and a silica sphere [Ren et al., Soft Matter 11, 6192–6200 (2015)]. In this study, in order to quantitatively describe the dependence of the elastic response on the geometrical parameters of the deformed interfaces, we employed the resonance shear measurement (RSM) and investigated the deformation of the interfaces between a flat DN gel and silica spheres by varying the curvature radius (R = 18.3, 13.8, 9.2, 6.9 mm). Resonance curves were analyzed using a mechanical model consisting of the elastic (k2) and viscous (b2) parameters of the contact interface. The obtained elastic parameter (k2) increases at higher loads and for smaller silica spheres, while the viscous parameter (b2) was negligibly low for all the conditions. The relations between the elastic parameter (k2), geometric parameters of the deformed contact interface, and the applied normal load were investigated. The elastic parameter (k2) was found to be proportional to the arc length (arc) (radius of contact area, r), i.e., k2 ∝ arc or k2 ∝ r. We introduced the term "elastic modulus of the contact interface, Econtact" as a proportionality constant to describe the elastic parameter of the deformed interfaces (k2): k2 (N/m) = arc (m) × Econtact (Pa). Thus, the friction (f) between the DN gel and the silica sphere can be described by the following equation: f = felastic = arc (m) × Econtact (N/m2) × Δx (m) (Δx: shear deformation of the contact interface between the DN gel and silica sphere). The Econtact value determined from the slope k2 vs arc was 493 ± 18 kPa. The RSM measurement and the analysis presented here can be a unique method for characterizing the specific properties of the deformed interfaces between soft and hard materials. [ABSTRACT FROM AUTHOR]

While the issue of properly describing the out-of-plane bends (OPBs) in sp2 hybridized carbon atoms has reappeared for c-SiC2H2, the present quantum chemical study provides a new characterization of this molecule in order to aid in its potential detection in astrophysically relevant studies. Combining the previous, high-level approach with MP2-F12/aug-cc-pVDZ gives exceptionally accurate results for the comparison of experimental rotational constants and seemingly reliable vibrational frequencies. Most notably, the brightest fundamental vibrational frequency in c-SiC2H2, the b1 OPB, is predicted to lie at 673.4 cm−1, within 4.0 cm−1 of the previous matrix isolation experiment. As with c-C3H2, CCSD(T)-F12/aug-cc-pVTZ appears to be quite susceptible to over estimating the OPB anharmonic correction in c-SiC2H2 and may also do such for in-plane bends, as well. MP2-F12/aug-cc-pVDZ is less susceptible to these errors, and increasing the step size reduces this positive anharmonicity issue in both the cases. The OPB underestimation, however, likely still remains. Finally, estimates for some anharmonic vibrational frequencies are provided for the methylated form, c-SiC2HCH3, which is likely also a product of gas phase reactions of ·SiH with various alkynes. [ABSTRACT FROM AUTHOR]

The free energy of adhesion per unit area (hereafter referred to as the adhesion strength) of lipid arrays on surfaces is a key parameter that determines the nature of the interaction between materials and biological systems. Here we report classical molecular simulations of water and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers at model silica surfaces with a range of silanol densities and structures. We employ a novel technique that enables us to estimate the adhesion strength of supported lipid bilayers in the presence of water. We find that silanols on the silica surface form hydrogen bonds with water molecules and that the water immersion enthalpy for all surfaces varies linearly with the surface density of these hydrogen bonds. The adhesion strength of lipid bilayers is a linear function of the surface density of hydrogen bonds formed between silanols and the lipid molecules on crystalline surfaces. Approximately 20% of isolated silanols form such bonds but more than 99% of mutually interacting geminal silanols do not engage in hydrogen bonding with water. On amorphous silica, the bilayer displays much stronger adhesion than expected from the crystalline surface data. We discuss the implications of these results for nanoparticle toxicity. [ABSTRACT FROM AUTHOR]

This paper presents the development of certain abrasives based on selected industrial wastes and gives an idea of their postuse behavior. These abrasives are manufactured using two methods: pulverization and coating. For these purposes, we used cellulosic nonwoven fibers as reinforcement, three types of resin (polyurethane, acrylic, and polyester) as a matrix, and abrasive grains of silicon carbide (SiC) and silica to obtain the abrasive character. We report the wear of the developed materials by abrasion, the evaluation of their roughness, the influence of the type of the abrasive grains, and their sizes on the wear performances. Scanning electron microscopy was performed to show the morphology of abrasives. The weight loss of abrasives was measured by thermogravimetric analysis and its derivative. Fourier‐transform infrared spectroscopy allows the chemical characterization and identification of abrasive grains. Under the same test conditions, experimental results indicate that silica‐based abrasives exhibit higher surface roughness and abrasion wear rate than SiC‐based abrasives. [ABSTRACT FROM AUTHOR]

We conducted laboratory experiments to investigate a suspected effect of tetrahydrofuran (THF) on quantifying crystalline silica in samples collected from working with engineered stone when THF is used to process samples prior to the X-ray diffraction (XRD) analysis. Two groups of samples from grinding either engineered stone or granite were simultaneously taken from a laboratory testing system, with one group of samples using THF for processing and another group using muffle furnace for ashing. For each stone type, we also tested four levels of respirable dust loading on the samples by varying the grinding time from 1 to 8 min. Statistical analysis of the experimental results on crystalline silica contents of the two groups of samples showed that the difference between the two methods was not significant (P ≥ 0.05) for the granite at all four levels of respirable dust loading and for the engineered stone at the two levels of respirable dust loading greater than 0.5 mg. However, the crystalline silica content from using THF processing was significantly lower (P = 0.001) than that from using muffle furnace ashing for engineered stone when the respirable dust loading levels were less than 0.5 mg. For the engineered stone dust samples with grinding times of 1 and 2 min, the average respirable dust loading was about 0.19 and 0.34 mg, respectively; while the crystalline silica content from using THF processing was 30.9 and 21.5% lower than that from using muffle furnace ashing, respectively. Since most full-shift samples from field assessments in this industry are expected to have respirable dust loading less than 0.5 mg, muffle furnace or radio frequency plasma ashing should be specified as the preferred sample processing method instead of the THF processing method for quantification of crystalline silica when engineered stone is expected to present to avoid artificially reduced silica content values, which are likely caused by the reactions between THF and the resins in engineered stone. [ABSTRACT FROM AUTHOR]

In the ever-expanding complexities of the modern-day mining workplace, the continual monitoring of a safe and healthy work environment is a growing challenge. One specific workplace exposure concern is the inhalation of dust containing respirable crystalline silica (RCS) which can lead to silicosis, a potentially fatal lung disease. This is a recognized and regulated health hazard, commonly found in mining. The current methodologies to monitor this type of exposure involve distributed sample collection followed by costly and relatively lengthy follow-up laboratory analysis. To address this concern, we have investigated a data-driven predictive modeling pipeline to predict the amount of silica deposition quickly and accurately on a filter within minutes of sample collection completion. This field-based silica monitoring technique involves the use of small, and easily deployable, Fourier transform infrared (FTIR) spectrometers used for data collection followed by multivariate regression methodologies including Principal Component Analysis (PCA) and Partial Least Squares (PLS). Given the complex nature of respirable dust mixtures, there is an increasing need to account for multiple variables quickly and efficiently during analysis. This analysis consists of several quality control steps including data normalization, PCA and PLS outlier detection, as well as applying correction factors based on the sampler and cassette used for sample collection. While outside the scope of this article to test, these quality control steps will allow for the acceptance of data from many different FTIR instruments and sampling types, thus increasing the overall useability of this method. Additionally, any sample analyzed through the model and validated using a secondary method can be incorporated into the training dataset creating an ever-growing, more robust predictive model. Multivariant predictive modeling has far-reaching implications given its speed, cost, and scalability compared to conventional approaches. This contribution presents the application of PCA and PLS as part of a computational pipeline approach to predict the amount of a deposited mineral of interest using FTIR data. For this specific application, we have developed the model to analyze RCS, although this process can be implemented in the analysis of any IR-active mineral, and this pipeline applied to any FTIR data. [ABSTRACT FROM AUTHOR]

In order to explore and study the preparation of elastic silica aerogel, it is studied and discussed on the basis of SEM. The overall effect, comprehensive performance, and coupling degree of the preparation of silica gel are compared and analyzed by conventional analysis method and SEM analysis method, and it can be clearly seen that the SEM analysis method is better than the previous conventional analysis method. The scanning speed, working distance, imaging resolution, and result accuracy of the SEM analysis method are higher. At the same time, the SEM analysis method is simpler than the ideal process. According to the special properties of the material itself, the nanoporous materials are with high porosity, high specific surface area, low density, and low thermal conductivity; and the porous three-dimensional spatial network structure, in optics, electricity is widely used in thermal insulation, environmental protection, catalysis, chemical industry, and other fields. Based on SEM, the instrument has high resolution, deep image field, three-dimensional sense, simple sample preparation, and comprehensive analysis; the silica aerogel has a spatial network structure, with an aperture range of 10~50 nm; compared with ordinary silica aerogel gel, the preparation of elastic silica aerogel can withstand higher temperature based on SEM analysis; stable quality and elasticity expand the application range of aerogel gel, making it more widely used in shock absorption, heat insulation, sound insulation, and other fields, effectively achieving the goal of energy conservation and emission reduction. [ABSTRACT FROM AUTHOR]

The thin-layer chromatography technique (TLC) is a simple and inexpensive analysis commonly used to identify qualitatively the presence of carbohydrates in food samples such as mono-di and oligosaccharides particularly. TLC assay could be improved using image processing software for the semiquantitative determination of this type of compound. In the present work, TLC-image analysis with Silica Gel 60 TLC plates was used for the semiquantitative determination of 6 standards of carbohydrates (glucose, fructose, sucrose, 1-kestose, nystose, and fructofuranosylnystose). Subsequently, the areas of the spots of each compound were determined by digitizing in a conventional office scanner. Then, the segmentation of the images is carried out using software for image processing. The calibration curves were plotted in the Excel software using the average of the areas of the pigmentations obtained in pixels. In this study, the technique of thin-layer chromatography was also used to quantitatively determine the presence of carbohydrates in food samples such as honey, garlic, and onion. Values of determination coefficient (R2) greater than 0.97 in all the calibration curves were obtained. This technique could be useful for detecting carbohydrates (monosaccharides, disaccharides, and oligosaccharides) in analytical assays and food samples without needing specialized analytical equipment. In this work, it was possible to determine the concentration of carbohydrates in samples of garlic and onion that showed the presence of prebiotic carbohydrates in addition to sucrose, glucose, and fructose. [ABSTRACT FROM AUTHOR]

Biosensors play a pivotal role in diagnosis through specific receptor‐ligand interactions. However, receptor biomolecules such as proteins have inevitable stability issues due to denaturation. Alternatively, utilization of the small molecules multivalently presented on porous silica particles as receptor components is considered to address the stability issues. A series of receptor components was synthesized using carbohydrates as a chiral scaffold to support multiple functional groups. The synthesized molecules were attached on the porous silica particles. Raman spectral analyses of single silica particles in the presence of nitrobenzene derivatives revealed a specific interaction with 4‐nitrophenol among others using a confocal Raman microscope. Chiral selective recognition was also accomplished for (1S,3S)‐ and (1R,3R)‐2‐amino‐1‐(4‐nitrophenyl)‐1,3‐propanediols. Protected carbohydrate derivatives are shown to be useful as receptor components on porous silica particles. [ABSTRACT FROM AUTHOR]

Halitosis is formed mainly by the volatile compounds produced by periodontal bacteria. Three volatile sulfur compounds (VSCs), hydrogen sulfide, methanethiol, and dimethyl sulfide, have attracted attention as major components of halitosis. However, these compounds cannot account for all odors. In this study, we profiled volatile compounds from the culture supernatants of periodontal bacteria using gas chromatography/mass spectrometry/olfactometry analysis with a monolithic silica gel adsorption device to investigate the potential odorous compounds. Periodontal bacteria have been found to produce volatile compounds belonging to various classes, such as alcohols, ketones, fatty acids, and aromatic compounds, in addition to VSCs. In addition, VSCs different from hydrogen sulfide and methanethiol, which are considered important causative compounds, may also influence to halitosis. [ABSTRACT FROM AUTHOR]

Magnesium potassium phosphate cement (MKPC) is extensively employed in patching materials and fireproof coatings owing to its outstanding properties. This study employs a blend of fly ash and silica fume to substitute a portion of the cementitious materials, aiming to enhance the performance of MKPC under high-temperature conditions. The relative proportions of fly ash and silica fume were considered. MKPC was subjected to cubic compression and three-point flexural tests. Additionally, the phase and microstructure of MKPC were also characterized using XRD and SEM. The compressive strength, flexural strength, visual appearance, and mass loss of MKPC specimens were evaluated before and after exposure to various high temperatures. Following exposure to elevated temperatures, MKPC specimens without fly ash and silica fume doping showed a significant decrease in strength. Conversely, specimens doped with 15 % or 10 % silica fume exhibited the most remarkable strength enhancement. The dehydration of K-struvite at elevated temperatures was the primary reason for the mass loss and strength reduction of MKPC. Silica fume and fly ash can facilitate the sintering of phases and amorphous particles derived from K-struvite decomposition, leading to the formation of ceramic-like structures. Notably, the contribution of silica fume to the sintering effect exceeds that of fly ash. Therefore, blending fly ash and silica fume proves to be an effective approach to enhancing the high-temperature resistance of MKPC. [Display omitted] • The influence of the relative content of fly ash and silica fume on the high-temperature performance of MKPC was examined. • Fly ash and silica fume significantly enhanced the mechanical properties of MKPC after exposure to high temperatures. • Fly ash and silica fume did not influence the hydration products of MKPC before and after exposure to high temperatures. • Notably, silica fume contributes more to the sintering effect compared to fly ash. [ABSTRACT FROM AUTHOR]

Background: Skin cutaneous melanoma (SKCM) is the deadliest skin cancer and has the most rapidly increasing incidences among all cancer types. Previous research elucidated that melanoma can only be successfully treated with surgical abscission in the early stage. Therefore, reliable and specific biomarkers are crucial to melanoma diagnosis since it often looks like nevi in the clinical manifestations. Moreover, identifying key genes contributing to melanoma progression is also highly regarded as a potential strategy for melanoma therapy. In this respect, translation initiator eIF6 has been proved as a pro-tumor factor in several cancers. However, the role of eIF6 in the skin cutaneous melanoma progression and its potential as a prognostic marker is still unexplored. Methods: The immunochemical analysis of clinical specimens were served to assess eIF6 expression levels. Gene Expression Profiling Interactive Analysis (GEPIA) database consultations allowed us to find the survival rates of the eIF6-overexpressed patients. eIF6 cellular effects were evaluated in an eIF6-overexpressed A375 cell line constructed with a lentivirus. The analysis of down-stream effectors or pathways was conducted using C-Bioportal and STRING databases. Results: Our results revealed that eIF6 was highly over-expressed in melanomas compared to normal skin specimens, and thus the abnormally high level of eIF6 can be a diagnostic marker for melanoma. The in silica analysis indicated that patients with eIF6 over-expression had lower survival rates than that low-expression in SKCM. Meanwhile, similar results also could be found in the other four types of cancers. In vitro , over-expression of eIF6 increased the proliferation and migration of melanoma cells. Correspondingly, pan-cancer clustering analysis indicated the expression level of intermediate filament proteins was correlated with that of eIF6 expression. In our study, all over-expressed keratin proteins, in accordance with over-expressed eIF6, had a negative correlation with melanoma prognosis. Moreover, the decreased methylation level of keratin genes suggested a new potential regulation mode of eIF6. Conclusions: The up-regulated eIF6 could be a potential diagnostic and prognostic biomarker of melanoma. This study also provides insights into the potential role of eIF6 in pan-cancer epigenetic regulation. [ABSTRACT FROM AUTHOR]

Vibrational spectroscopy has been widely used to investigate various structural aspects of the glass network, and there are a plethora of papers reporting subtle but consistent changes in infrared and Raman spectral features of glass upon alterations of glass compositions, thermal histories, mechanical stresses, or surface treatments. However, interpretations of such spectral features are still obscured due to the lack of well‐established physical principles accurately describing vibrational modes of the non‐crystalline glass network. Due to the non‐equilibrium nature of the glass network, three‐dimensionally connected without any long‐range orders, vibrational spectral features of glass cannot be interpreted using the analogy with those of isolated molecular moieties or crystalline counterparts. This feature article explains why such comparisons are outdated and describes the recent advances made from theoretical calculations of vibrational spectral features of amorphous networks or comparisons of computational results with experimental data. For the interpretation of vibrational spectral features of silica and silicate glasses, the following empirical relationships are suggested: (i) the intensity‐weighted peak position of the Si‐O‐Si stretch mode negatively correlates with the weighted average of the Si‐O bond length distribution, and (ii) the broad band of the Si‐O‐Si bending mode negatively correlates with the Si‐O‐Si bond angle distribution. Selected examples of vibrational spectroscopic imaging of surface defects are discussed to deliberate the implication of these findings in the structure‐property relationship of silica and silicate glass materials. Unanswered questions and continuing research challenges are identified. [ABSTRACT FROM AUTHOR]

The dissolved silica structures in quartz-saturated 0.50 and 1.50 m [mol kg H2O–1] Na2CO3 and 0.47 m NaOH solutions at up to 750 °C and 1.5 GPa were investigated by in-situ Raman spectroscopy using a Bassett-type hydrothermal diamond anvil cell. The solubility of quartz in the solutions was determined by in-situ observations of the complete dissolution of the grain. The Raman spectra of the quartz-saturated Na2CO3 and NaOH solutions at high pressures and temperatures exhibited the tetrahedral symmetric stretching band of silica monomers. The lower frequency and broader width of the band than those in pure H2O indicated the presence of both neutral and deprotonated monomers. In addition, we newly confirmed the intense bridging oxygen band and the tetrahedral symmetric stretching band of Q1 (silicate center having a single bridging oxygen atom) in the spectra of the Na2CO3 solutions. The integrated intensity ratios of the bridging oxygen band to the monomer band increased with the addition of Na2CO3 and NaOH to fluids, corresponding to an elevation of the measured quartz solubilities. These observations indicate that the formation of silica oligomers in addition to neutral and deprotonated monomers explains the high dissolved silica concentrations in the solutions. The presence of deprotonated monomers under the experimental conditions suggests that deprotonated oligomers exist in the solutions, because the production of the latter more significantly reduces the Gibbs free energy. The anionic silica species and oligomers formed in alkaline silicate fluids may act as effective ligands for certain metal ions or complexes in deep subduction zones. [ABSTRACT FROM AUTHOR]

Open science is an integral part of all scientific research, but the extent of open science practices in phytolith research is unknown. Phytolith analysis examines silica bodies that are initially formed within and between plant cells during the life of the plant but become deposited in sediments once the plant dies. The use of phytoliths in archaeobotanical and palaeoecological studies has been increasing in recent years resulting in an upsurge in publications. The aims of this article are to assess open science practices in phytolith research by reviewing data and metadata sharing, and open access, in a sample of journal articles containing primary phytolith data from 16 prominent archaeological and palaeoecological journals (341 articles). This study builds on similar studies conducted for zooarchaeology (Kansa et al. 2020) and macrobotanical remains (Lodwick 2019). This study shows that 53% of papers shared data in any format but only 4% of papers contained reusable data, 74% included some pictures of phytolith morphotypes for identification purposes, 69% had a fully described method, 47% used the International code for phytolith nomenclature (ICPN 1.0) and only 13% of articles were open access. Steps forward are then proposed, including planning for open projects, making more articles openly accessible and implementing the FAIR data principles, to use as a starting point for discussions in the wider phytolith and archaeological communities to develop guidelines for greater integration of open science practices. [ABSTRACT FROM AUTHOR]

The properties of silica are important to geophysical and high-pressure equation-of-state research. Its most-prevalent crystalline form, α-quartz, has been extensively studied to TPa pressures. This article presents Hugoniot measurements on amorphous silica, commonly referred to as fused silica, over a range from 200 to 1600 GPa using laser-driven shocks and an α-quartz standard. These results extend the measured Hugoniot of fused silica to higher pressures. In the 200- to 600-GPa range, the data are in very good agreement with those obtained by Qi et al. [Phys. Plasmas 22, 062706 (2015)] using magnetically driven aluminum impactors and aluminum as a standard material. A new shock velocity/particle velocity relation is derived to fit the experimental data. [ABSTRACT FROM AUTHOR]

Vibrational spectroscopy is frequently used to characterize nanoconfined liquids and probe the effect of the confining framework on the liquid structure and dynamics relative to the corresponding bulk fluid. However, it is still unclear what molecular-level information can be obtained from such measurements. In this paper, we address this question by using molecular dynamics (MD) simulations to reproduce the linear infrared (IR), Raman, and two-dimensional IR (2D-IR) photon echo spectra for water confined within hydrophilic (hydroxyl-terminated) silica mesopores. To simplify the spectra the OH stretching region of isotopically dilute HOD in D2O is considered. An empirical mapping approach is used to obtain the OH vibrational frequencies, transition dipoles, and transition polarizabilities from the MD simulations. The simulated linear IR and Raman spectra are in good general agreement with measured spectra of water in mesoporous silica reported in the literature. The key effect of confinement on the water spectrum is a vibrational blueshift for OH groups that are closest to the pore interface. The blueshift can be attributed to the weaker hydrogen bonds (H-bonds) formed between the OH groups and silica oxygen acceptors. Non-Condon effects greatly diminish the contribution of these OH moieties to the linear IR spectrum, but these weaker H-bonds are readily apparent in the Raman spectrum. The 2D-IR spectra have not yet been measured and thus the present results represent a prediction. The simulated spectra indicates that it should be possible to probe the slower spectral diffusion of confined water compared to the bulk liquid by analysis of the 2D-IR spectra. [ABSTRACT FROM AUTHOR]

Two-dimensional silica is of rising interests not only for its practical applications as insulating layers in nanoelectronics, but also as a model material to understand crystals and glasses. In this study, we examine structural and electronic properties of hexagonal and haeckelite phases of silica bilayers by performing first-principles calculations. We find that the corner-sharing SiO4 tetrahedrons in these two phases are locally similar. The robustness and resilience of these tetrahedrons under mechanical perturbation allow effective strain engineering of the electronic structures with band gaps covering a very wide range, from of that for insulators, to wide-, and even narrowgap semiconductors. These findings suggest that the flexible 2D silica holds great promises in developing nanoelectronic devices with strain-tunable performance, and lay the ground for the understanding of crystalline and vitreous phases in 2D, where bilayer silica provides an ideal test-bed. [ABSTRACT FROM AUTHOR]

In the surface treated inorganic particles with silane coupling agent (SCA), chemisorbed and physisorbed molecules are present in the treated layer. Increasing the amount of chemisorption by increasing the molecular weight of SCAs was investigated. Oligomers formed via self‐condensation during storage more than 10 days at room temperature for 3‐methacryloxypropyltrimethoxysilane‐treated silica particles. Monomeric SCA evaporates easily by heating. The oligomers restrict evaporation, and heating increases the chemisorption. The influence of molecular weight of SCA was investigated. In the case of amino group, the amount of chemisorbed was greater for aminoethylaminooctyltrimethoxysilane with high molecular weight than for 3‐aminopropyltriethoxysilane. For SCAs with hydrocarbon chains, the amount of chemisorption was lower for both low molecular weight molecules and decyltrimethoxysilane (D) with a high molecular weight. For fluorocarbon chains, the amount of chemisorption was lower for low molecular weight molecules, whereas it increased significantly by heating for high molecular weight type of 1H,1H,2H,2H‐heptadecafluorodecyltriethoxysilane (F). Wide‐angle X‐ray diffraction analysis of F‐treated silica particles showed that the fluorocarbon chains formed an ordered structure. There was no such indication for the D‐treated system. This ordered structure seems to influence on higher chemisorption for F‐treated systems. [ABSTRACT FROM AUTHOR]

As semiconductor devices have become miniaturized and highly integrated, interconnection problems such as RC delays, power dissipation, and crosstalk appear. To alleviate these problems, materials with a low dielectric constant should be used for the interlayer dielectric in nanoscale semiconductor devices. Silica aerogel as a porous structure composed of silica and air can be used as the interlayer dielectric material to achieve a very low dielectric constant. However, the problem of its low stiffness needs to be resolved for the endurance required in planarization. The purpose of this study is to discover the geometric effect of the electrical and mechanical properties of silica aerogel. The effects of porosity, the distribution of pores, the number of pores on the dielectric constant, and elastic modulus were analyzed using FEM. The results suggest that the porosity of silica aerogel is the main parameter that determines the dielectric constant and it should be at least 0.76 to have a very low dielectric constant of 1.5. Additionally, while maintaining the porosity of 0.76, the silica aerogel needs to be designed in an ordered open pores structure (OOPS) containing 64 or more pores positioned in a simple cubic lattice point to endure in planarization, which requires an elastic modulus of 8 GPa to prevent delamination. [ABSTRACT FROM AUTHOR]

The origin and growth mechanisms of microcrystalline quartz cement in sandstones and its relationship to quartz overgrowths remain puzzling even though it has an important effect on rock properties in deeply buried sandstones; microcrystalline quartz cement inhibits the growth of quartz cement and so leaves sandstones with anomalously high porosity deep in sedimentary basins. Here we have examined the relationships between quartz cement, and duplicate layers of chalcedony/amorphous silica and microcrystalline quartz from outcrops of the Upper Cretaceous Heidelberg Formation, Germany. We have used an array of techniques including: NanoSIMS for spatially-resolved stable oxygen isotope analysis, and high-resolution chemical analysis of the silica cements using electron microprobe analysis, as well as crystallographic studies using TEM and EBSD. Based on burial history modeling and the low degree of compaction of the Heidelberg Formation sandstones, we conclude that maximum temperature due to conductive heating was about 42 °C; quartz overgrowths with δ18O of 18.8 ‰ developed from meteoric-derived formation water with δ18O of about −12 ‰ V-SMOW. Based on published precedents and an awareness that silica solubility decreases with decreasing temperature, we assume that chalcedony/amorphous silica and then microcrystalline quartz developed during cooling of flowing formation water. Chalcedony with δ18O of 27.4 ‰ developed from meteoric-derived formation water with δ18O of between −1 and −3 ‰ V-SMOW depending on whether the initial temperature of the cooling formation water was 45 or 55 °C. The interpreted higher δ18O of the warmer water responsible for chalcedony and microcrystalline quartz growth is typical of basin-center waters that have undergone considerable water–rock interaction. It is likely that the fluid movement was caused by thrust tectonics in the Coniacian to Campanian. The duplicate layers of chalcedony/amorphous silica and then microcrystalline quartz suggests that there were two thrust-induced fluid expulsion events. [ABSTRACT FROM AUTHOR]