Submicron Size Research Articles

Synthesis of submicron ferrous oxalate from red mud with high Fenton catalytic performance on degradation of methylene blue.

Ferrous oxalate dihydrate (FOD) can be used as a photo-Fenton catalyst with remarkable photo-Fenton catalytic and photocatalytic performances on organic pollutant degradation. Various reduction processes were compared in the current study to synthesize FODs from ferric oxalate solutionutilizing the iron source in alumina waste red mud (RM), including natural light exposure (NL-FOD), UV light irradiation (UV-FOD), and hydroxylamine hydrochloride hydrothermal method (HA-FOD). The FODs were characterized and employed as photo-Fenton catalysts for methylene blue (MB) degradation, and the effects of HA-FOD dosage, H2O2 dosage, MB concentration, and the initial pH were investigated. The results show that HA-FOD has submicron sizes and lower impurity contents with more rapid degradation rates and higher degradation efficiencies compared with the other two FOD products. When using 0.1g/L of each obtained FOD, 50mg/L of MB can be rapidly degraded by HA-FOD by 97.64% within 10min with 20mg/L of H2O2 at pH of 5.0, while NL-FOD and UV-FOD achieve 95.52% in 30min and 96.72% in 15min at the same conditions, respectively. Meanwhile, HA-FOD exhibits strong cyclic stability after two recycling experiments. Scavenger experiments reveal that the predominant reactive oxygen species responsible for MB degradation are hydroxyl radicals. These findings demonstrate that submicron FOD catalyst can be synthesized using hydroxylamine hydrochloride hydrothermal process from ferric oxalate solution with high photo-Fenton degradation efficiency and reduced reaction time for wastewater treatment. The study also provides a new pathway of efficient utilization for RM.

Tailoring hierarchical BiVO4 sub-micron particles for enhanced cyclability in asymmetric supercapacitor

This work demonstrates the feasibility of sub-micron size metal oxides as a sustainable charge storage material in supercapacitors fabrication and addressing the cycle instability issues of pseudocapacitors. The sub-micron bismuth vanadate (BiVO4) particles were synthesized by two different routes, co-precipitation (BVO-N) and sonochemical (BVO-S) methods. The morphological investigation of BVO-S showed hierarchical microspheres with diameter ranges of 1–6 μm, which is more prominent in size compared to BVO-N particles (100 nm- 1-μm in diameter). The nitric acid plays a crucial role in stabilizing the BiVO4 particles in the co-precipitation process, whereas ultrasonic waves predominantly control the spherical particle formation in the sonochemical route. The electrochemical performance of BVO-N and BVO-S was tested in a potassium hydroxide (KOH) electrolyte. The charge and discharge cycle experiments showed BVO-S microspheres are more highly stable than that BVO-N. The BVO-N starts to degrade with its initial capacitance beyond 1000 cycles. The poor stability of BVO-N may be due to the breakdown of surface-adsorbed charged ionic species. As a result, BVO-S performs with a higher specific capacitance value of 214 F/g compared to BVO-N (124 F/g). Trasatti analysis revealed a balanced, synergistic behaviour of pseudocapacitance (61 %) and electric double layer capacitance (39 %) at the BVO-S is responsible for their high specific capacitance compared to BVO-N. The BVO-S has low intrinsic resistance due to the highly denser micro-spherical structure, allowing electrolyte ions to access the inner and outer surfaces of the BVO-S. Interestingly, charge transfer resistance was decreased after the cyclic stability test due to electrochemical activation and facilitates fast ion transport increasing the surface contact area of active material at the electrode-electrolyte interface. We fabricate the asymmetric cell with BVO-S microspheres (anode), activated carbon particles (cathode) and Poly (ethylene oxide) (PEO) /Polyethene glycol dimethyl ether (PEGDME)/KOH gel-based electrolyte. This asymmetric supercapacitor performs with a specific capacitance value of 153 F/g at 0.3 A/g under the cell voltage of 1.2 V. Also, it delivers 30.6 Whkg−1 of energy density and 1983 W kg−1 of power density. The cyclic stability of 98 % over 5000 cycles was achieved in this configuration. This performance is appreciable compared to the previous work on BiVO4-based asymmetry supercapacitors, particularly a capacitance retention (%) and potential window. Overall, an acid-free sonochemical processing route reported in this work is highly environmentally friendly. Likewise, the sub-micron metal oxide particle significantly improves their electrochemical stability without the coalesced together with any carbonaceous material. It can be transferred to synthesizing a broader choice of metal oxide based for enhanced cyclability with effective utilization of their charge storage behaviour that will perform high-power storage, which powers short-distance electric transportation.

Electrostatic Charging of Fine Powders and Assessment of Charge Polarity Using an Inductive Charge Sensor

Electrostatic charging of powders becomes important, when particles become smaller, especially for fine powders at micron or sub-micron size. Charging of powders causes strong particle adhesion and consequently difficulties in processes such as blending or mixing, and sieving, etc. Not only does the charge of powders influence the process and the quality of the products, but also the discharge creates risks of dust explosion. Assessing powder charge and the hazards in manufacturing can be difficult. One of the major challenges is to evaluate the charge levels and polarity in the powders but this requires a significant number of tests to detect charge tendency and distributions in bulk materials, which is time-consuming. In this paper, electrostatic charging of powders in material handling processes and the associated hazards are briefly reviewed. For an assessment, the challenges for sensing electrostatic charges of particulate solids, particularly for fine powders, are discussed. It was revealed that sensing the charge polarity for representative samples of powders can be the main challenge because of the difficulty in separation of the charged particles. The inductive charge sensor showed great potential to measure charge levels and polarity distributions in powders. Experimental trials for several fine powders showed that the inductive charge sensor can be used for rapidly assessing chargeability and charge polarity distribution of powders.

Preparation of isotropic submicron spherical boron nitride particles by restricted template method

AbstractHexagonal boron nitride (h‐BN) has received considerable attention, due to its high thermal conductivity and electrical insulation. However, the intrinsic platelike structure with the strong anisotropic property restricts its applications, and it is necessary to synthesize isotropic spherical h‐BN particles (SP‐BNs) with submicron size. Till now, methods to prepare (SP‐BN) still exist problems, such as high oxygen impurities and pollution, generated by the ammonia and pyrolysis of precursors. Here, a relatively green reaction between the restricted template of carbon nanospheres and boron trioxide (B2O3) under elevated temperature is conducted, and the SP‐BNs with an average diameter of 200–300 nm (named Nano‐BN‐s) have been successfully synthesized. Comprehensive scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction characterizations confirm the obtained products are spherical boron nitride. With the analysis of X‐ray photoelectron spectroscopy and Fourier transform infrared, the reaction mechanism is briefly discussed. These results indicate the reaction occurs on the restricted template of carbon nanospheres, and the C atoms are substituted by B and N atoms as the reaction progress, forming the Nano‐BN‐s. What is more, the restricted template method plays a key role in the design and improves h‐BN‐based materials in the future and may also be extended to form other novel materials.

ANTARES: Space-resolved electronic structure

The spatially resolved ARPES (nanoARPES) is a development of conventional ARPES technique achieved with the focusing of light on the sample into the spot with submicron sizes. This development is used in research of essentially small samples, for example, heterostructures build of flakes of 2D materials, micro-crystals or polycrystalline samples, different crystal termination, domains in electronic structure. ANTARES is delivering the nanoARPES technique to user community since 2010, up to now the instrument was used with samples of various types, and that was useful to accumulate the specific experience. In this paper we report the current layout and actual performance of the ANTARES instrument at Synchrotron SOLEIL, as well as the most typical application areas. The most important and recent upgrades include focusing optics and in-operando setup. The new optical units deliver the increased flux on sample as well as the option to vary the photon energy. The in-operando setup offers the option of electrical connection to the sample being studied with nanoARPES, that promises various applications, where the most demanded now is the control of charge carrier density with applied voltage. This “gate-doping” is often applied to the heterostructures of 2D materials, that could be designed and build on purpose. The 2D heterostructures is probably the most typical field of application of the instrument, with or without in-operando option. At the same time the use case of the ANTARES instrument is still in the development by the realisation of new kinds of samples and of the new types of the experiments.

Synthesis of plate-like cordierite using a small amount of H3BO3 flux

This work aimed to prepare high-purity, plate-like cordierite powder at a lower cost. Kaolin, talc and alumina were used as the starting materials for cordierite synthesis, and only a small amount of boric acid (H3BO3) was used as the flux. Despite the limited amount of liquid phase formed, the addition of H3BO3 could effectively promote the formation of plate-like cordierite polycrystals, which might be related to the gas-phase-mass transfer of molten boron trioxide (B2O3) at high temperatures and the selective adsorption of [BO3] on different crystal planes during crystallization. Moreover, it is necessary to closely control the calcining temperature, as the morphological development of cordierite polycrystals was sensitive to temperature. Plate-like α-cordierite polycrystals with submicron size could be obtained with the addition of 3 wt% H3BO3 at a calcining temperature of 1180 °C. This study broadens the range of complex oxides that can be obtained by the flux method and provides some references for the preparation of cordierite powder with good sinterability.

Three-dimensional propagation behavior of hydrogen-related intergranular cracks in high-strength martensitic steel

Using X-ray computed tomography and focused ion beam-scanning electron microscopy (FIB-SEM) serial sectioning, this study investigated the three-dimensional propagation behavior of hydrogen-related intergranular cracks in martensitic steel with a tensile strength of 1.2 GPa, focusing on segments of prior austenite grain boundaries (PAGB segments). X-ray computed tomography revealed that the crack morphology was more continuous in the hydrogen-charged specimens. Through FIB-SEM serial sectioning, we found that crack-tip blunting and ductile rupture of un-cracked ligaments were associated with specific PAGB segments in the uncharged specimen. In the case of hydrogen-related intergranular crack propagation, even very fine, low-angle PAGB segments (sub-micrometer size) can act as obstacles for crack propagation. Based on these results, we propose that the misorientation of each PAGB segment has a large influence on the local arrestability of intergranular crack propagation.

The size distribution of SARS-CoV-2 genetic material in airborne particles sampled in hospital and home care environments occupied by COVID-19 positive subjects

Characterizing the size distribution of airborne particles carrying SARS-CoV-2 virus is essential for understanding and predicting airborne transmission and spreading of COVID-19 disease in hospitals as well as public and home indoor settings. Nonetheless, few data are currently available on virus-laden particle size distribution. Thus, the aim of this study is reporting the total concentrations and size distributions of SARS-CoV-2- genetic material in airborne particles sampled in hospital and home environments. A nanoMOUDI R122 cascade impactor (TSI, USA) was used to collect size-segregated aerosol down to the sub-micron range in home and in three different hospital environments in presence of infected patients in order to provide the concentration of airborne SARS-CoV-2 genetic material for each particle size range at different sampling locations. Providing one of the largest datasets of detailed size-fractionated airborne SARS-CoV-2 RNA to date, we found that 45.2 % of the total sub- and super-micrometric fractions were positive for SARS-CoV-2 with its genetic material being present in 17.7 % of sub-micrometric (0.18–1 μm) and 81.9 % of super-micrometric (>1 μm) fractions. The highest concentration of SARS-CoV-2 genetic material in total suspended particles (5.6 ± 3.4 RNA copies m−3) was detected in the room occupied with patients with more severe COVID-19 symptoms collected during the patients' high flow nasal oxygen therapy. The highest concentration at certain particle size fraction strongly depends on the sampling environment. However, the contribution of SARS-CoV-2 genetic material was in favour of super-micrometric compared to sub-micrometric particle size range. The evaluation of the individual risk of infection was carried out on the basis of the obtained data considering a hypothetical exposure scenario. The obtained results indicate the necessity of the protective masks in presence of infected subjects, especially while staying for longer period of time in the hospital environments.

Microscopic and elemental analysis of jaw bone tissue in injury

Since the jawbone tissue is injured at the stage of metal dental implant introduction, the problem of inflammatory complication development leading to a breakdown in osseointegration remains relevant. Of interest are the immunological mechanisms of inflammatory process development during the emission of metal nanoparticles, as well as the mechanisms of its subsidence after the removal of a metal object. Microscopic and elemental analysis of the bone tissue of the Wistar rat lower jaw after artificial traumatization was carried out. During the experiment, the situation of presence of a metal foreign body in the bone bed was simulated. An insulin needle was injected into the connective tissue of the lower jaw, followed by its removal after seven days. Microscopic analysis of bone tissue was performed using a Tesscan Vega 4 scanning electron microscope. The teeth alveoli cortical layer surface, connection of the jaws with a gap, stratification of the cartilaginous layer were determined at low magnification in direct projection. Using higher magnification in the direct projection there are visible dense-structural crystalline inclusions, foci of necrosis in the area of junctions of the jaws alveolar processes. The elemental composition of bone tissue was obtained by atomic emission spectroscopy by iCAP 6300 Duo. In the test sample, the quantitative ratio of calcium and phosphorus was 1.68, which slightly exceeds the optimal value of 1.67. An upward change in this ratio indicates a decrease in phosphorus level, which can be interpreted as local osteoporosis. In addition, the following elements were found: Bi, Ga, Pb, Ti, Zn in the amount of 0.03-0.06 mass percent. The list of these elements corresponds to the chemical composition of an insulin needle, indicating the penetration of metal particles into bone bed tissues. The emission of nanoparticles and their subsequent association to micro- and submicron sizes, their persistence, as well as biocorrosion in areas of active bone formation can be a trigger for the development of an aseptic inflammatory process. This effect is due to both a direct damaging factor and an indirect effect through specific signal molecules produced in response to tissue damage.

Variables Impacting Silicone Oil Migration and Biologics in Prefilled Syringes

Prefilled syringes (PFS) as a primary container for parenteral drug products offer significant advantages, such as fast delivery time, ease of self-administration and fewer dosing errors. Despite the benefits that PFS can provide to patients, the silicone oil pre-coated on the glass barrels has shown migration into the drug product, which can impact particle formation and syringe functionality. Health authorities have urged product developers to better understand the susceptibility of drug products to particle formation in PFS due to silicone oil. In the market, there are multiple syringe sources provided by various PFS suppliers. Due to current supply chain shortages and procurement preferences for commercial products, the PFS source may change in the middle of development. Additionally, health authorities require establishing source duality. Therefore, it is crucial to understand how different syringe sources and formulation compositions impact the drug product quality. Here, several design of experiments (DOE) are executed that focus on the risk of silicone oil migration induced by syringe sources, surfactants, protein types, stress, etc. We utilized Resonant Mass Measurement (RMM) and Micro Flow Imaging (MFI) to characterize silicone oil and proteinaceous particle distribution in both micron and submicron size ranges, as well as ICP-MS to quantify silicon content. The protein aggregation and PFS functionality were also monitored in the stability study. The results show that silicone oil migration is impacted more by syringe source, siliconization process and surfactant (type & concentration). The break loose force and extrusion force across all syringe sources increase significantly as protein concentration and storage temperature increase. Protein stability is found to be impacted by its molecular properties and is less impacted by the presence of silicone oil, which is the same inference drawn in other literatures. A detailed evaluation described in this paper enables a thorough and optimal selection of primary container closure and de-risks the impact of silicone oil on drug product stability.

Effects of Salinity Beyond Coalescence on Submicron Aerosol Distributions

AbstractBubbles entrained by ocean waves rise to the surface and burst, creating a shower of droplets which contribute to sea spray aerosols. Submicron‐sized droplets, of which an estimated 60%–80% come from a bursting bubble film cap, play a key role in global climate atmospheric processes. However, many aspects of predicting the number and size of submicron drops emitted from a bursting bubble remain unknown. It is well‐documented that higher salinity increases submicron droplet production, which has been attributed to the role of salt in the suppression of bubble coalescence. We experimentally show that submicron drop production increases with salinity despite using a salt that does not affect bubble coalescence, indicating that salinity plays a role in the physics of submicron aerosol formation beyond coalescence. Laboratory experiments are conducted using sodium acetate solutions of salinity S = 0.001–0.1 M with millimeter‐sized bubbles generated via a needle. Unlike previous studies, the measured droplet size distributions are converted to formation diameter, revealing that the peak aerosol formation diameter decreases with higher salinity. Applying this diameter conversion to past studies, we find the peak formation diameter exhibits a scaling of Dform ∼ S−0.32 across three orders of magnitude in salinity and for a variety of salts, bubble coalescence behaviors, and bubble generation mechanisms. This result suggests that salinity has a systematic effect on the length scale of the rupturing bubble film which generates the aerosols. Consequently, salinity likely impacts the submicron aerosol production in oceanic environments even if bubble coalescence is negligible.

Characterization of Virus Particles and Submicron-Sized Particulate Impurities in Recombinant Adeno-Associated Virus Drug Product

Characterization of particulate impurities such as aggregates is necessary to develop safe and efficacious adeno-associated virus (AAV) drug products. Although aggregation of AAVs can reduce the bioavailability of the virus, only a limited number of studies focus on the analysis of aggregates. We explored three technologies for their capability to characterize AAV monomers and aggregates in the submicron (<1 µm) size range: (i) mass photometry (MP), (ii) asymmetric flow field flow fractionation coupled to a UV-detector (AF4-UV/Vis) and (iii) microfluidic resistive pulse sensing (MRPS). Although low counts for aggregates impeded a quantitative analysis, MP was affirmed as an accurate and rapid method for quantifying the genome content of empty/filled/double-filled capsids, consistent with sedimentation velocity analytical ultracentrifugation results. MRPS and AF4-UV/Vis enabled the detection and quantification of aggregate content. The developed AF4-UV/Vis method separated AAV monomers from smaller aggregates, thereby enabling a quantification of aggregates <200 nm. MRPS was experienced as a straightforward method to determine the particle concentration and size distribution between 250-2000 nm, provided that the samples do not block the microfluidic cartridge. Overall, within this study we explored the benefits and limitations of the complementary technologies for assessing aggregate content in AAV samples.

A comprehensive review on applications, preparation &amp; characterization of nanoemulsion

With time, dosage forms have progressed, from essential tablets to advanced systems, which are now more focused on providing better ease of administration to the patients. One such advantageous novel drug delivery system is Nanoemulsion based drug delivery. The Nanoemulsion-based system is reasonably a new means of enhancing drug delivery; Nanoemulsions are sub-micron size particles roughly in the size range of 50-600 nm. The review focuses on conveying information by combining various articles and study reports to understand the work done in this field. This review paper aims to serve as a tool to understand the development of Nanoemulsion. The study comprehensively analyses the preparation methods, composition, characterization, and stability and their application in drug delivery via various routes. Lastly, the paper also describes the recent five formulations prepared for nanoemulsions and their applicability as discussed in the literature.

152 Top-down Preparation and Characterization of Crystalline Nanosilica for Toxicological Investigations

Abstract Crystalline silica (CS) is a well-known human carcinogen and freshly fractured CS is strongly held to be more toxic than aged dust. Mechanical fracturing indeed generates on CS surface a specific family of Nearly-Free Silanols (NFS), a moiety that was proved to destabilize cell membranes and initiate inflammation in vivo. During milling, silica nanoparticles are also generated, however their contribution to the overall toxicity of quartz is still largely unexplored. Nanoquartz can be synthetized via bottom-up methods, but the surface chemistry of those crystals strongly differs from nanoparticles resulting from fracturing. We report here a top-down milling procedure to obtain a nanometric quartz that shares with fractured quartz the key surface properties relevant to toxicity. Fracturing procedure was optimized by coupling dry and wet milling steps, using water as a dispersing agent, and varying milling times and rotational speeds. We obtained a set of samples that would be classified as nanomaterials under EU CLP regulation (&amp;gt;50% of particles in number are &amp;lt; 100 nm) and exhibited a strong tendency to form submicrometric agglomerates. Deagglomeration with surfactants or simulated body fluids was negligible. Partial lattice amorphization and bimodal crystallite domain size were observed, as confirmed by the presence of two distinct domains of scattering with nanometric (&amp;lt; 50 nm) and submicrometric (0.8-1 µm) crystallite size. A moderate membranolytic activity, which nicely correlated with the amount of surface NFS, signalled that our nanoquartz may induce inflammation in vivo. Overall, a membranolytic nanoquartz for investigating the toxic activity of nanometric silica was obtained.

Nanosized Proton Conductor Array with High Specific Surface Area Improves Fuel Cell Performance at Low Pt Loading.

The use of ordered catalyst layers, based on micro-/nanostructured arrays such as the ordered Nafion array, has demonstrated great potential in reducing catalyst loading and improving fuel cell performance. However, the size (diameter) of the basic unit of the most existing ordered Nafion arrays, such as Nafion pillar or cone, is typically limited to micron or submicron sizes. Such small sizes only provide a limited number of proton transfer channels and a small specific area for catalyst loading. In this work, the ordered Nafion array with a pillar diameter of only 40 nm (D40) was successfully prepared through optimization of the Nafion solvent, thermal annealing temperature, and stripping mode from the anode alumina oxide (AAO) template. The density of D40 is 2.7 × 1010 pillars/cm2, providing an abundance of proton transfer channels. Additionally, D40 has a specific area of up to 51.5 cm2/cm2, which offers a large area for catalyst loading. This, in turn, results in the interface between the catalyst layer and gas diffusion layer becoming closer. Consequently, the peak power densities of the fuel cells are 1.47 (array as anode) and 1.29 W/cm2 (array as cathode), which are 3.3 and 2.9 times of that without array, respectively. The catalyst loading is significantly reduced to 17.6 (array as anode) and 61.0 μg/cm2 (array as cathode). Thus, the nanosized Nafion array has been proven to have high fuel cell performance with low Pt catalyst loading. Moreover, this study also provides guidance for the design of a catalyst layer for water electrolysis and electrosynthesis.

Production of Al2O3-SiC composites from micrometer α-Al2O3 powder obtained via sol-gel

Alumina (Al2O3) is an advanced ceramic material developed for different applications as refractories, precision tools, pacemaker, etc. Solid state sintering of alumina or matrix ceramic composites (CMCs) compacts starts from powders. Once method to produce high quality aluminum oxide powders is the sol-gel technique. Alumina begins as pseudo-crystallized aluminum hydroxide gel which is produced under moderate reaction conditions trough a colloidal suspension. In this work, Al2O3 powder was produced by precipitation of pseudoboehmite (PB) through sol-gel process. Subsequently, a mixture of Al2O3/SiC powders with 5 wt.% of SiC as reinforcement was produced. This mixture was used to manufacture green compacts by uniaxial pressing at 440 MPa. Afterward, some samples were applied a heat treatment (pre-sintered) at 1200°C for 6 h in air. Sintering was carried out in a vertical dilatometer Linseis L75 V up to 1500°C for 2h under argon atmosphere. Pseudobohemite, alumina powders and Al2O3/SiC composites were characterized through X-ray diffraction technique and Scanning Electron Microscopy (SEM). Dilatometric shrinkage data into densification curves obtained were analyzed. Images obtained with SEM showed a uniform Al2O3 powder morphology of submicron size, otherwise Al2O3/SiC composite images showed the interaction of the reinforcement particles on the ceramic matrix. Experimental results demonstrated the pre-sintering reduce the decomposition of SiC particles on the compact surface. This behavior was attributed to formation of SiO2 around the reinforcement particle due it act as protective barrier.

Design of silica coated polyamide fabrics for thermo‐regulating textiles

AbstractEfficient thermal management is essential for the energy balance and thermal comfort. In this context, the design of textiles, which can modulate the infrared radiation emitted by the human body, is attractive. These fabrics will manage the microclimate between the skin and fabric. The proposed textile design consists of the coating of commercial woven fabrics based on polyamide 6–6 by a dip‐coating process. The coating is based on the incorporation of fine spherical silica particles with a submicron size within thermosensitive poly(N‐isopropylacrylamide) hydrogels. Neat commercial fabrics reflect 12% of the radiation, while the addition of silica particles leads to a reflection of 24% of the infrared radiation in the 5–15 μm wavelengths range. The infrared radiation reflection capacity of the coated fabrics can be increased by managing the size and the content of the silica particles, which allows reaching 36% of reflected radiation. Our findings open opportunities for warming up fabrics and thus reduce energy consumption in heating close space.

Facile Synthesis of Ultra-microporous Pillar-Layered Metal-Organic Framework Membranes for Highly H2-Selective Separation.

Recently, pillar-layered MOF materials have attracted much attention and shown great potential in separation application due to their fine pore size/channel and pore surface chemistry tunability and designability. In this work, we reported an effective and universal synthesis strategy for preparing ultra-microporous Ni-based pillar-layered MOF [Ni2(L-asp)2(bpy)] (Ni-LAB) and [Ni2(L-asp)2(pz)] (Ni-LAP) (L-asp = L-aspartic acid, bpy = 4,4'-bipyridine, pz = pyrazine) membranes on a porous α-Al2O3 substrate with high performance and good stability by secondary growth. Through this strategy, the seed size reduction and screening engineering (SRSE) is proposed to obtain uniform sub-micron size MOF seeds by high-energy ball milling-combined solvent deposition. This strategy not only effectively addresses the issue of obtaining the uniform small seeds being significant for secondary growth but also provides an approach for the preparation of Ni-based pillar-layered MOF membranes where the freedom of synthesizing small crystals is lacking. Based on reticular chemistry, the pore size of Ni-LAB was narrowed by making use of shorter pillar ligands of pz instead of the longer pillar ligand of bpy. The prepared ultra-microporous Ni-LAP membranes exhibited a high H2/CO2 separation factor of 40.4 with H2 permeance of 9.69 × 10-8 mol m-2 s-1 Pa-1 under ambient conditions and good mechanical and thermal stability. The superiority of the tunable pore structure and the remarkable stability of these MOF materials showed great potential for industrial H2 purification. More importantly, our synthesis strategy demonstrated the generality for preparation of MOF membranes, enabling the regulation of membrane pore size and surface functional groups by reticular chemistry.

Abstract 998: A blood-based extracellular vesicles DNA methylation signature for colorectal cancer screening

Abstract Colorectal cancer (CRC) is the third most common cancer worldwide and the fourth leading cause of cancer related deaths, accounting for an estimated 1.8 million new cancer diagnoses and over 880,000 deaths in 2018. Furthermore, CRC patients who are diagnosed at the most advanced (metastatic) stage is estimated to have the 5-year survival rate of 14%. Dramatically, studies shows that if it can be detected at an early stage when surgical removal is feasible, the 5-year survival rate significantly increases to 90%. Therefore, early detection for CRC with curative treatment intent is crucially important to significantly reduce the mortality and morbidity and even cure CRC. Extracellular vesicles (EVs) are lipid-bilayer-enclosed vesicles of sub-micrometer size that are secreted by virtually all cell types. They contain hundreds of different proteins, thousands of intact RNA species, and double-stranded DNA (dsDNA) fragments that sample the entire human genome. Recent findings further corroborate the potential role of EVs in early cancer screening, cancer diagnosis, treatment selection and monitoring. In this study, we used lipid nanoprobe (LNP) for EV isolation and methylation-specific qPCR assay for detecting SEPT9 methylation to develop a minimal invasive CRC screening test. Firstly, we have successfully detected promoter methylation of cancer specific genes SEPT9 in EVs derived from both genomic DNA and EV DNA of the CRC cell line. Secondly, we isolated EV using LNP from plasma samples in a cohort of 19 CRC patients and 9 healthy donor controls. In parallel, we isolated circulating free DNA (cfDNA) from the same cohort of the plasma samples using commercially cfDNA isolation Kit. Then, SEPT9 methylation signature was analyzed by our quantitative real-time PCR assay in these 28 EV DNA samples and 28 cfDNA samples, respectively. In the 19 CRC samples, we identified 10 SEPT9 gene methylation samples from LNP-isolated EV DNA and cfDNA, respectively. In 9 healthy control samples, no SEPT9 methylation was detection in the EV-DNA samples, while one false-positive was detected with cfDNA. Thus, the sensitivity and specificity of EV-DNA in the detection of SEPT9 gene methylation from CRC were determined to be 53% and 100% respectively. In comparison, the sensitivity and specificity of cfDNA are 53% and 89%, respectively from this preliminary pilot study. This indicated that EV-DNA might be superior to cfDNA in detecting SEPT9 gene methylation for CRC screening. Citation Format: Sheng Zhang, Faming Wang, Mingxi Chen, Jeongyun Kim, Mengrou Lu, Hongzhang He, Siyang Zheng. A blood-based extracellular vesicles DNA methylation signature for colorectal cancer screening [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 998.

The Effect of Thermodeformation Treatment on the Structure and Strengthening of the Al–7.1% Zn–2.8% Mg–1.4% Ni–1.1% Fe Alloy Produced via Casting in an Electromagnetic Crystallizer

A calculation technique (Thermo-Calc software code) and experimental methods (scanning and transmission electron microscopy and X-ray spectral analysis) have been used to study the effect of thermodeformation treatment on the structure and strengthening of the Al–7.1% Zn–2.8% Mg–1.4% Ni–1.1% Fe alloy produced via casting in an electromagnetic crystallizer (EMC). It has been shown that at a cooling rate higher than 103 K/s, the entire amount of iron, which exceeds its content in the grade AZ6NF alloy (GOST 4784–2019) by two times, is bound into eutectic inclusions of the Al9FeNi phase of a submicron size. Thecombination of high hardness (more than 190 HV) and ductility indicates the advantages of applying the EMC technology to this alloy.