Correlation of Efficient Dispersion and Catalytic Performance of Nanocombustion Catalysts in Energetic Materials: A Case Study of the Nanocopper Oxide Catalyst with Superfine Ammonium Perchlorate.

Obviously, the dispersion of nanocatalytic materials has significant influence on their catalytic performance. In this study, an evaluation method for the dispersion of nanomaterials was established according to the different solid UV absorptions of different substances by taking the dispersion of nanocopper oxide (nano-CuO) in superfine ammonium perchlorate (AP) as an example. The nano-CuO/superfine AP composites with different nano-CuO dispersions can be obtained by changing the process parameters, such as varying the grinding method, the grinding strength, and the grinding time. Three replicate experiments were carried out for different composites to derive the average values of absorbance at 212 nm, and the dispersion of nano-CuO in superfine AP was calculated using the difference equation, as the solid UV curves at 210-214 nm were almost identical for each sample, especially at 212 nm. The properties of different samples were tested by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), differential scanning calorimetry (DSC), and thermogravimetry-mass spectrometry (TG-MS). The results show that the particle size and structure of superfine AP in the composites prepared by different methods were not changed. The XRD and IR techniques in this study were unable to characterize the dispersion of nano-CuO in the composites due to its low content. The dispersion of nano-CuO in the nano-CuO/superfine AP composites was significantly enhanced with the increase of grinding strength and grinding time, and the dispersion of nano-CuO was positively correlated with its catalytic performance, which means that the thermal decomposition performance of different composites improved with the increasing dispersion of nano-CuO. Highly dispersed nano-CuO exhibited a significant catalytic effect on superfine AP in TG-MS. The above conclusions demonstrate the accuracy of the difference equation for evaluating the dispersion of nanomaterials based on solid UV curves, which is expected to be used extensively in evaluating the dispersion of nanocatalytic materials in energetic materials.

Correction to "Study on Effective Well Depth of Single U-Shaped Vertical Buried Pipe Based on Temperature Difference Analysis".

[This corrects the article DOI: 10.1021/acsomega.3c01207.].

The positive correlation between the dispersion and catalytic performance of Fe2O3 nanoparticles in nano-Fe2O3-ultrafine AP energetic composites supported by solid UV-vis spectroscopy.

Recently, the widespread use of nanocatalytic materials has contributed to an enormous improvement in the performance of energetic materials, especially, highly dispersed nanomaterials. However, the lack of quantitative methods for analyzing the dispersion of nanomaterials limits their further widespread use. Although various techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), etc. are used to analyze the relative dispersion of nanomaterials, it is not possible to quantitatively analyze their dispersion. Therefore, there has been an effort to develop new methods for the quantitative analysis of nanocatalytic materials. Fortunately, we were able to analyze the dispersion of nanocatalytic materials using the difference in their UV absorbance. More importantly, we established the corresponding difference equation to quantify the dispersion of nanocatalytic materials, which is capable of quantifying the dispersion of nano-Fe2O3 in nano-Fe2O3-ultrafine AP composites. The accuracy of the difference equation was verified using a variety of techniques and the desired results were obtained. Based on the above conclusions, the quantitative analysis method for the dispersion of nanomaterials that we established is expected to be widely used and promote the development of energetic materials.

Experimental Study on the Effect of Pitch Sloshing on the Heat Transfer and Pressure Drop of an LNG Spiral-Wound Heat Exchanger.

With the development and utilization of offshore liquefied natural gas, it is increasingly important to study the influence of the heat transfer performance of a spiral-wound heat exchanger under sloshing conditions. This study focused on the effects of different sloshing amplitudes and sloshing periods on the heat transfer and pressure drop performance of a heat exchanger. Through experimental research, the results showed that the fluctuation of the UA (U is the heat transfer coefficient; A is the heat exchange area) value first increased and then decreased with an increase in the sloshing amplitude. The UA value increased by 12.92% and decreased by 42.03% compared to the static value at 3 and 9°, respectively. The fluctuation in the UA value first decreased and then increased with an increase in the sloshing period. The UA value decreased by 36.66% and increased by 10.82% slowly compared to the static value when the sloshing period was 6 and 20 s, respectively. Based on this, a mathematical model of heat transfer under the condition of pitch sloshing was established.

Study on the Effective Well Depth of Single U-Shaped Vertical Buried Pipes Based on Temperature Difference Analysis.

A heat transfer model of a single U-shaped vertical buried pipe similar to an actual scenario is established, and the accuracy of the model is verified by experiments. The model is used to analyze the heat transfer performance of vertical buried pipe heat exchangers with well depths of 200, 160, 120, and 80 m. This includes the heat transfer per unit well depth, temperature change of the well wall and fluid along the pipe length, heat transfer coefficient, and section heat transfer validity. With the increase in well depth, the heat exchange per unit well depth decreases, and the proportion of heat exchange in the inlet section to the total heat exchange increases. When the well depths are 200, 160, 120, and 80 m, the last 10 m pipe sections have 30, 40.3, 53.7, and 66.4% of the heat exchange efficiencies of the initial 10 m pipe section, respectively. To obtain a reasonably effective well depth of a single U-shaped vertical buried pipe, it is necessary to comprehensively consider the heat exchange per unit well depth, the temperature difference between the well wall and the fluid, and the energy efficiency of the buried pipe section. Moreover, it should be analyzed in combination with economic factors.

Experimental Study on the Slugging Characteristics of Gas-Liquid Slug Flow in Horizontal Pipes.

This study investigates the slugging characteristics of the gas-liquid slug flow interface in horizontal pipes. Using air and water as the experimental media, an experimental system was established using double-parallel conductance probes in a pipe with an inner diameter of 5 cm. By capturing the transient development process of the gas-liquid interface, the slugging characteristics of the gas-liquid two-phase flow interface in different flow regions were revealed. The results show that the value of gas-phase superficial velocity has an important influence on the shape and development of the interface wave during the slugging process. When the gravity wave generated during the slugging process can propagate upstream, the slugging phenomenon is periodic, and when the gravity wave cannot propagate upstream, the slugging phenomenon is random. The experiment verified the correctness of the interface instability theory and the liquid slug stability theory, and clarified the definitions of h o and h s. In addition, the paper analyzed the influence of gas-liquid velocity on slugging distance, h o and h s, and liquid slug frequency.

Development of organogel-based emulsions to enhance the loading and bioaccessibility of 5-demethylnobiletin.

5-Demethylnobiletin (5-DMN), identified in the aged citrus peels, has received increasing attentions due to its outstanding bioactivity among citrus polymethoxyflavones (PMFs). However, the poor water solubility and high crystallinity limit its oral bioavailability. Besides, the solubility of 5-DMN in the oil is very limited, which restricts its loading capacity in emulsions for bioavailability enhancement. In this study, an organogel formulation was developed to improve the solubility of 5-DMN in medium-chain triacylglycerols by 3.5 times higher without crystal formation during 5-day storage at room temperature. Increasing the gelator (i.e., sugar ester) concentration led to the increase of viscosity and a gel-like structure of the organogel. The ternary phase diagram of organogel-based emulsions was explored, and 40% organogel was selected as the oil phase for emulsion preparation. Increasing the concentration of Tween 80 from 0% to 6% decreased the droplet size and viscoelasticity of the emulsions. Two in vitro models, the pH-stat lipolysis model and TNO gastro-intestinal model (TIM-1), were applied to investigate the bioaccessibility of 5-DMN in different delivery systems. Compared with the conventional emulsion and oil suspension, the pH-stat lipolysis demonstrated that the organogel-based emulsion was the most efficient tool to enhance 5-DMN bioacccessibility. Moreover, TIM-1 digestive study indicated that 5-DMN bioaccessibility delivered by organogel-based emulsions was about 3.26-fold higher than that of oil suspension. Our results suggested that the organogel-based emulsion was an effective delivery route to enhance the loading and bioaccessibility of lipophilic compounds of high crystallinity.

Prediction and New Insight for the Drag Reduction of Turbulent Flow with Polymers and Its Degradation Mechanism.

A physicochemical understanding of the mechanism of turbulent flow drag reduction with polymer and its degradation is of great interest from both science and industry perspectives. Although the correlation based on the Fourier series has been proposed to predict the drag reduction and its degradation, its physical meaning was not clear until now. This letter aims to clarify this issue. We develop a comprehensive model to predict the drag reduction and degradation of polymers in turbulent flow from a chemical thermodynamics and kinetics viewpoint. We demonstrate that the Fourier series employed to predict the drag reduction and its degradation is due to the viscoelastic property of drag-reducing polymer solution, and the phase angle in the model, in physical nature, represents the hysteresis of the polymer in turbulent flow. Besides, our new insight of drag reduction with flexible polymers can also explain why a maximum drag reduction in rotational flow appears before degradation happens.

Evaluation of the bioaccessibility of tetrahydrocurcumin-hyaluronic acid conjugate using in vitro and ex vivo models.

Tetrahydrocurcumin-hyaluronic acid (THC-HA) conjugate was synthesized in order to improve the bioaccessibility of tetrahydrocurcumin (THC). The successful conjugation was confirmed by the results from 1H-nuclear magnetic resonance (1H NMR), Differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Bioaccessibility enhancement from the THC-HA conjugate compared to the free crystalline THC suspension was demonstrated by the results from ex vivo Franz diffusion cell using small intestine from porcine and in vitro TNO dynamic gastrointestinal model-1 (TIM-1). Additionally, in vitro release was studied, and the integrity of the conjugate in both simulated gastric and intestinal conditions was found to maintain for up to 4 h. Mucoadhesive assay and rheological results indicated that the mucoadhesive property of THC-HA, in combination with the aqueous solubility enhancement, might contribute to the increased bioaccessibility. This study provides a promising approach to enhance the bioaccessibility of tetrahydrocurcumin through the innovative conjugation with hyaluronic acid.

Assessment of Oral Bioavailability and Biotransformation of Emulsified Nobiletin Using In Vitro and In Vivo Models.

Nobiletin has received much attention for its promising biological activities. Owing to its limited solubility, various encapsulation strategies have been developed to enhance nobiletin bioavailability. However, the understanding of the bioavailability and biotransformation of nobiletin in vivo and the correlation between in vitro and in vivo data remains limited. This study developed a high-loading nobiletin (1%) emulsion. The in vitro models, which combined pH-stat lipolysis with a Franz cell, showed very good correlation with in vivo data for the relative bioavailability. Rat studies showed that nobiletin had a high absolute bioavailability (≈20% for oil suspension). Besides, the emulsification improved the amount of bioavailable nobiletin and its major metabolite in the blood by about two times, as compared to an oil suspension. This work provides scientific insights into a rapid screening method for delivery systems and a better understanding of the biological fate of nobiletin in vivo.

Comparative Analyses of Bioavailability, Biotransformation, and Excretion of Nobiletin in Lean and Obese Rats.

Nobiletin, one of the prevalent polymethoxyflavones in citrus peels, was reported to possess various health benefits. We conducted the excretion study and pharmacokinetics study of nobiletin via oral administration and intravenous injection and 15 day consecutive dosing study using the high fat diet-induced obese rats and their lean counterparts. By comparing the demethylated metabolite profiles in the urine and feces, gut microbiota demonstrated greater biotransformation activity on nobiletin than the host. The absolute oral bioavailability of nobiletin in lean (22.37% ± 4.52%) and obese (18.67% ± 4.80%) rats has a negligible statistically significant difference (P > 0.05). However, a higher extent of demethylated metabolites was found in the feces and plasma of obese rats than lean rats (P < 0.05). Moreover, the consecutive dosing of nobiletin might lead to a higher extent of demethylated metabolites in the plasma and in feces. These results suggested that gut microbiota played important roles in nobiletin metabolism.

Synthesis of a well-dispersed CaFe2O4/g-C3N4/CNT composite towards the degradation of toxic water pollutants under visible light.

Herein, we fabricated a ternary photocatalyst composed of CaFe2O4, multiwalled carbon nanotubes (CNTs) and graphitic carbon nitride (g-C3N4) via a simple hydrothermal route. CaFe2O4 acted as a photosensitizer medium and the CNT acted as a co-catalyst, which remarkably enhanced the photocatalytic performances of g-C3N4 towards the degradation of hexavalent chromium (Cr(vi)) and the antibiotic tetracycline (TC) under visible light irradiation. To investigate the morphological and topological features of the photocatalyst, field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) analyses were performed. The surface properties and oxidation state of the CaFe2O4/g-C3N4/CNT composite were determined by X-ray photoelectron spectroscopy (XPS). The recombination rate of the charge carriers and the band gap values of the as-synthesized catalysts were analyzed by photoluminescence spectroscopy (PL) and diffused reflectance spectroscopy (UV/Vis DRS) studies, respectively. Besides the degradation reactions, the high hydrogen production rate of 1050 µmol h-1 under visible light using the CaFe2O4/g-C3N4/CNT composite loaded with 5 wt% CNT was observed. The superior photocatalytic performances of the CaFe2O4/g-C3N4/CNT composite can be ascribed to the effective heterojunction formed between g-C3N4 and the CaFe2O4 matrix, in which the CNT act as a conducting bridge in the system, promoting the production of photoinduced charge carriers in the semiconductor system. Finally, the plausible photocatalytic mechanism towards the degradation of pollutants and hydrogen production was discussed carefully.

Correction: Synthesis of a well-dispersed CaFe2O4/g-C3N4/CNT composite towards the degradation of toxic water pollutants under visible light.

[This corrects the article DOI: 10.1039/C9RA05005A.].

[Gene rearrangement pattern of immunoglobulin and T-cell receptor (Ig/TR) and its clinical characteristics in children with SET-NUP214 fusion gene-positive leukemia/lymphoma].

The purpose of this study was to analyze the gene rearrangement pattern of immunoglobulin and T-cell receptor (Ig/TR) and its clinical characteristics in three children with SET-NUP214 fusion gene positive leukemia/lymphoma. The transcript of SET-NUP214 fusion gene was detected by RT-nested PCR. The pattern of Ig/TR gene rearrangement was analyzed by using the BIOMED-2 multiplex PCR assays. Allelic-specific primers were designed for further monitoring the minimal residual disease (MRD). The results indicated that the fusion site located between exon 7 of SET and exon 18 of NUP214 at mRNA level in the three patients. The diagnoses were made as the mixed phenotype of acute leukemia (MPAL) for patients 1, acute T-lymphoblastic leukemia (T-ALL) for patients 2, and stage IV T-lymphoblastic lymphoma (T-LBL) for patients 3, respectively. Patient 1 responded to chemotherapy very poorly and relapsed at month 6 after hematopoietic stem cell transplantation. Patient 2 had high MRD (> 10(-2)) at the end of inducing remission therapy (day 33) which implied poor outcome, and died of toxic epidermal necrolysis and sequent serious infection. Patient 3 achieved hematological complete remission (CR) and MRD negative at day 15 and day 33 respectively. The duration of CR lasted for 30 months. Clonal TR gene rearrangements were detected in all the three patients. The rearrangements of TRD, TRG and TRB were found in patient 1 and 3. The rearrangements of TRD, TRB, IgH and IgK Kde were detected in patient 2. All the 6 TRB rearrangements detected were incomplete rearrangements, whereas 85.7% and 14.3% of the TRD, and TRG rearrangements were complete and incomplete, respectively. It is concluded that the transformation of SET-NUP214(+) leukemia/lymphoma cells may occur after the rearrangements of TRD and TRG and shortly after TRB rearrangement. The leukemia/lymphoma cells of patient 1 and 2 are more immature which may be related with poor outcome or response to chemotherapy.

Bamboo charcoal as adsorbent for SPE coupled with monolithic column-HPLC for rapid determination of 16 polycyclic aromatic hydrocarbons in water samples.

The coupling of solid-phase extraction (SPE) using bamboo charcoal (BC) as an adsorbent with a monolithic column-high performance liquid chromatography (MC-HPLC) method was developed for the high-efficiency enrichment and rapid determination of 16 polycyclic aromatic hydrocarbons (PAHs) in water. Key influence factors, such as the type and the volume of the elution solvent, and the flow rate and the volume of the sample loading, were optimized to obtain a high SPE recovery and extraction efficiency. BC as an SPE adsorbent presented a high extraction efficiency due to its large specific surface area and high adsorption capacity; MC as an HPLC column accelerated the separation within 8 min because of its high porosity, fast mass transfer, and low-pressure resistance. The calibration curves for the PAHs extracted were linear in the range of 0.2-15 µg/L, with the correlation coefficients (r(2)) between 0.9970-0.9999. This method attained good precisions (relative standard deviation, RSD) from 3.5 to 10.9% for the standard PAHs I aqueous solutions at 5 µg/L; the method recoveries ranged in 52.6-121.6% for real spiked river water samples with 0.4 and 4 µg/L. The limits of detection (LODs, S/N = 3) of the method were determined from 11 and 87 ng/L. The developed method was demonstrated to be applicable for the rapid and sensitive determination of 16 PAHs in real environmental water samples.