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In this research, AlN nano-powders were prepared by combining carbon-containing droplet combustion (CCDC) and carbothermal reduction (CR) methods. Firstly, Al 2 O 3 +C mixed precursor was synthesized by the CCDC method, and then AlN nano-powder was obtained by the carbothermal reduction of this CCDC precursor. The effects of urea and glucose contents, ignition temperature, and combustion atmosphere on precursors and AlN powders were studied in detail. The results showed that with the molar ratio of urea to aluminum nitrate (U/A) of 3, the atomic ratio of carbon to aluminum (C/Al) of 6, and the ignition temperature at 800 °C under air atmosphere, the prepared precursor was composed of hollow and spherical structure particles exhibiting rough and porous surface morphology with high specific surface area (SSA) (41.4 m2/g). AlN nano-powders obtained by the carbothermal reduction of this precursor were found to be consisted of fine particles with the size of 20–30 nm with high SSA of 39.9 m2/g. [ABSTRACT FROM AUTHOR]

Using citric acid, ethylene glycol, ZrOCl 2 ·8H 2 O, HfOCl 2 ·8H 2 O, NbCl 5 , and TaCl 5 as raw materials, based on the principle of Pechini coordination polymerization, the (Zr 0.25 Hf 0.25 Ta 0.25 Nb 0.25)C high-entropy ceramic precursor solution was successfully prepared, and the corresponding high-entropy ceramic powder was formed by pyrolysis at a low temperature of 1500 °C. The molecular structure of the precursor and its pyrolysis products were analyzed and characterized by different analytical and testing methods. The results show that in the precursor solution, the organic compound and the metal ions form a stable three-dimensional macromolecular structure, so that the metal ions show a uniform distribution at the molecular level, shortening the diffusion path during the carbothermal reduction reaction, thereby enabling the formation of the single-phase high-entropy carbide ceramic powders at a relatively low temperature. The obtained ceramic powders have high purity, uniform element distribution, with an average particle diameter of approximately 42 nm and an oxygen content of about 1.61 wt%. The precursor solution prepared in this study has a moderate viscosity of 20–50 mPa s and a high ceramic yield of 45 %, which is ideal for the preparation of high-entropy ceramic matrix composites. [ABSTRACT FROM AUTHOR]

The geopolymerization reaction is a chemical process involving the dissolution of amorphous, semi-crystalline and crystalline phases following alkaline or acid attack at ambient or at low temperature (T˂100 °C). Together with precondensed entities of the used activator solution the dissolved parts form a geopolymer network which glues together all remaining unreacted parts as ingredients of the artificial stone. The fate of the mineralogical phases present in the precursors used in the synthesis of alkaline and acid geopolymers is reviewed in this article. The different starting materials used in the synthesis of geopolymers and the different techniques used to modify the reactivity of these materials are reported. The mineralogical evolution of the amorphous, semi-crystalline and crystalline phases after activation at ambient and at low temperatures (T < 100 °C) is also reported. This study shows that for the mineralogical investigation of raw material, precursors and geopolymers, XRD is the most widely used analytical method. The most commonly used method to confirm the participation of crystalline phases in geopolymerization is the comparison of the diffractograms of the raw material to those of the products. It also indicates that, in addition to the amorphous aluminosilicate phases, certain semi-crystalline, and crystalline phases participate in this geopolymerization dynamic either by undergoing total or partial dissolution to form an inorganic macromolecule with an amorphous structure of the zeolitic type and other new minerals. The composition of the phases formed depends on the base material. Increasing the synthesis temperature promotes the dissolution of phases, the formation of geopolymer networks, and in some cases, the formation of new phases such as sodalities, zeolite A and zeolite P. Little work has been done to quantify the mineralogical phases before and after precursor activation, making it impossible to assess dissolution, the degree of geopolymerization, and mineral formation. The exact structure of the phases formed is often questionable, as most of the papers do not mention their reference structure number. There is also a lack of quantification of the amorphous phase resulting from the hardening of the activating solution and the evaluation of the fraction of the amorphous phase contained in the precursor remains unreacted. The mineralogical investigation must also extend to the quantification of phases using Rietveld refinement with internal standards to correlate these with the physical and mechanical properties of geopolymer products. Additional mineralogical study techniques, such as thin sections, should be used in future work for in-depth mineralogical investigation of geopolymers. [ABSTRACT FROM AUTHOR]

Diagnostic delays in Bipolar Disorder (BD) are common and may contribute to worse outcomes. While most studies focus on depression as a primary precursor, both anxiety and attention deficit disorders are also frequent initial diagnoses. In the current study, we utilized a large, diverse electronic health record (EHR) dataset to quantify the rates and correlates of conversion to BD from these major precursor diagnoses. Our study analyzed a comprehensive ten-year EHR dataset from Johns Hopkins Medicine, a diverse urban medical center, to assess and compare the rates and correlates of conversion to BD from Major Depressive Disorder (MDD), anxiety disorders, and ADHD. Risk factors for transition were assessed as time-varying variables in proportional hazards models. Of the 21,341 patients initially included, 1232 later transitioned to a diagnosis of BD. Adjusted-one-year conversion rates for patients with MDD, anxiety disorders, and ADHD were 4.2 %, 3.4 %, and 4.0 %, respectively, with ten-year rates at 11.4 %, 9.4 %, and 10.9 %, respectively. Age (19–29 years), treatment setting (emergency and inpatient), and psychotropic medications were associated with conversion to BD across all precursor diagnoses. Severe and psychotic forms of MDD were among the strongest risk factors for transitioning to BD. Although risk factors for convertion were similar, transition rates were lower in children, particularly in indivudals with ADHD, who showed a higher rate of BD conversion in adults. The highest risk of transitioning to BD was observed in patients initially diagnosed with MDD, though significant risk was also noted in those with initial diagnoses of anxiety disorders and adult ADHD. • Approximately 4% of patients "converted" to Bipolar Disorder (BD) within one year, increasing to ∼10% within ten years • Greater illess severity, psychotic symptoms, and treatment in higher acuity settings were all associated with an increased risk of an eventual coversion to BD • Diagnostic conversion rates were lower in children and highest in adults within the 19-29 age range • Risk factors for conversion were generally similar in children and adults • ADHD was associated with higher rates of conversion to BD in adults compared to children [ABSTRACT FROM AUTHOR]

The synthesis of hafnium carbide nanowires (HfC NWs) on carbon fibers was successfully achieved by employing HfCl 4 and furfuryl alcohol as precursor materials, facilitated by Ni-assisted catalytic pyrolysis. In the polymerization and cross-linking processes of furfuryl alcohol, hafnium cations play a crucial role, leading to the atomic-level amalgamation and effectively enhancing the reactivity of the Hf-O-C system. The nucleation of HfC NWs takes place at 1300 °C, followed by growth through a solid-liquid-solid (SLS) mechanism. Carbon fibers were uniformly coated with tens micrometer-long HfC NWs having an approximate diameter of 500 nm. Notably, the tips of these HfC NWs exhibited clean surfaces free of Ni catalyst particles, indicating their root growth model. This novel catalyst-assisted pyrolysis method holds great potential for enabling cost-effective large-scale production of transition metal carbide nanowires. [ABSTRACT FROM AUTHOR]

The commercialization of ternary layered cathode materials with a relative nickel content of more than 90 % faces serious challenges. Among them, it is urgent to address the issues of rapid capacity degradation and structural degradation. Herein, we provide a simple process for doping yttrium at the precursor preparation stage. The feasibility of yttrium doping in the precursor and the positive effects of yttrium ions on the crystal structure and properties of the cathode materials are scientifically explained by a variety of characterization and testing methods, such as Eh-pH, Particle Size Analyzer, ICP, SEM, EDS, XRD, XPS, HRTEM, dQ/dV, CV, EIS and DFT. Yttrium-doped NCMY cathode materials have more stable lattice oxygen and significantly less irreversible phase transition. Furthermore, the electrochemical performance of the NCMY cathode material is significantly improved, with a capacity retention rate of 82.71 % after 150 cycles at a current density of 1C, which is much higher than 65.39 % for NCM. The NCMY cathode material significantly improves the lithium ion diffusion ability, especially at the high rate of 10C, the discharge specific capacity is still as high as 177.05 mAh g−1. [ABSTRACT FROM AUTHOR]

• A powerful Mw = 7.2 earthquake occurred on August 14, 2021 at 12:29 UT. • Variations of electron density obtained from CSES-01 satellite were considered. • Findings acknowledge the sequence of seismic anomalies observed in the LAI. A powerful Mw = 7.2 earthquake occurred in Haiti on August 14, 2021 at 12:29:08 UTC (18.434° N, 73.482° W, depth ∼10 km). In this study, in a period of three months from June 1 to August 31, 2021, the variations in electron density and temperature parameters obtained from CSES-01 satellite measurements in the Dobrovolsky's area the Haiti earthquake are considered. With the aim of investigating the proposed mechanisms for interactions between different layers of the Earth in the process of earthquakes (LAIC-Lithospheric Atmospheric Ionospheric Coupling), the behavior of 48 other precursors obtained from the data of other satellites in the same location and time period were analyzed. These precursors are 1) TEC obtained from GPS satellite data, 2) scalar and vector magnetic field data as well as electron density and temperature measured by the related sensors of three Swarm A, B and C satellites during day and night and 3) Variations in lithospheric and atmospheric parameters NO2 and SO2 obtained from OMI satellite measurements and also Ozone, carbon monoxide and surface temperature parameters obtained from AIRS data. By analyzing the above mentioned precursors, abnormal behaviors are observed around 30 and 50 days before the earthquake, and especially 1 to 15 days before the earthquake and by comparative study of the observed anomalies, possible LAIC mechanisms are discussed. The findings of this study can acknowledge the sequence of seismic anomalies observed in the lithosphere, then the atmosphere and finally the ionosphere. Therefore, this study once again emphasizes the necessity of performing multi-precursor analysis with the aim of justifying the LAIC mechanism and also observing seismically prone anomalies in the time period of about 10 days before powerful earthquakes. [ABSTRACT FROM AUTHOR]

It has been found that CuZnAl slurry catalyst performance is influenced seriously by its precursors in ethanol synthesis from syngas. Herein, a series of the slurry catalysts were prepared by complete liquid phase method adopting different sol-gel and solution as components of precursors. Their catalytic performances were investigated in a slurry bed reactor and physicochemical properties were characterized by XRD, H 2 -TPR, NH 3 -TPD, N 2 adsorption and XPS techniques. The results show that the catalyst Al–Zn(g)-Cu(s) prepared by adopting Zn gel and Cu solution as components of precursors exhibits the highest ethanol synthesis capacity, with the proportion of ethanol in the total alcohol reaching up to 45.36%. And no visible deactivation was detected over 168 h reaction. Characterization indicates larger Cu0 particles and a suitable range of surface Cu0/(Cu0+Cu+) ratios are favorable to the production of ethanol, the Cu0/(Cu0+Cu+) ratios can be adjusted partly by Cu0 particle sizes. [Display omitted] • CuZnAl slurry catalysts directly catalyze syngas to ethanol without promoters. • The properties of precursors have a decisive influence on the catalyst performance. • The Cu0/(Cu0+Cu+) ratios can be adjusted partly by Cu0 particle sizes. • A proper Cu0/Cu+ ratio and Cu0 particles can maximize ethanol output. [ABSTRACT FROM AUTHOR]

In this study, the effects of precursor density on the size, distribution, and volume fraction of in-situ TiC particles were investigated through an analysis of high chromium cast iron (HCCI) matrix composites reinforced with in-situ TiC particles which were made through casting infiltration. The microstructure of different composites was observed, and their mechanical properties and wear resistance were analyzed. The results showed that with the increase of the precursor density from 2.954 g cm−3 to 3.546 g cm−3, the average size of the TiC particles grew from 0.19 μm to 0.66 μm, while their volume fraction decreased from 69.75% to 50.89%, and the compressive strength of the composites fell from 533 MPa to 428 MPa. When the precursor density was 2.954 g cm−3, the composites exhibited the best wear resistance, which was 1.98 times as good as those with the precursor density of 3.546 g cm−3. The wear mechanism of the abrasives in the composites lies in their cutting effect and the protection of TiC particles. The existence of a body of submicron TiC particles enhanced the deformation resistance of the matrix as they were able to reduce wear. This study contributes to the research of wear-resistant materials and enables them to be widely applied in the future. [ABSTRACT FROM AUTHOR]

Dynamic nuclear polarizing (DNP) technique in nuclear magnetic resonance (NMR) is a powerful tool for a microanalysis. Nevertheless, it has not been applied to analyses of carbon materials such as graphene oxide (GO) and amorphous carbon effectively because of the electroconductivity and microwave absorption of the carbon, which attenuate the enhancement effect of DNP. For this study, we applied DNP-NMR to analyses of surface functional groups on GO and sucrose-derived carbon to evaluate the method. The 1H–13C cross-polarization magic-angle spinning (CP/MAS) DNP-NMR of a GO sample with AMUPol (polarizing agent) showed 2.2-times-enhanced peaks of 13C in epoxide, bonding to hydroxyl group, and in the graphene plane. Signal enhancement was raised by AMUPol radicals neighboring the surface functional groups and the graphene planes on GO particles, although attenuation by temperature rise must be considered. Furthermore, additional new peaks assigned to CH 3 group on the GO particle surface were highly enhanced and were observed clearly only by the accumulations of 64 scans. For sucrose-derived carbon, DNP-NMR clearly revealed the –OH group on the carbon surface or carbon edge by heat treatment, which was not possible using conventional CP/MAS experiments. Cross Effect was found to be dominant in signal enhancements of the functional groups on GO and sucrose-derived carbon samples, except for the CH 3 groups on GO. The CH 3 enhancement is ascribed mainly to the Overhauser effect or solid effect. [Display omitted] • Dynamic nuclear polarizing was used for NMR measurement of carbon materials. • Surface functional groups on GO and sucrose-derived carbon were analyzed. • 1H–13C CP/MAS DNP-NMR of GO with polarizing agent showed enhanced peaks. • Methyl group signals on GO particle surfaces were highly enhanced. • DNP with appropriate radical sources can contribute to the surface analysis of carbon. [ABSTRACT FROM AUTHOR]

A deliberately selected end-capping agent was introduced into the precursor to form a low number average molecular weight precursor and meet the need for liquid crystal display (LCD) 3D printing. The influence of number average molecular weight on the photocuring properties of precursor and the physical properties of pyrolysis samples were studied in detail for the first time. The results proved that a relatively low number average molecular weight precursors had low ceramic yields after pyrolysis. As the number average molecular weight of the precursor decreased, the photocuring ability of the precursor photosensitive resin increased. With the decrease in the number average molecular weight of the precursor in the precursor photosensitive resin, the ceramic yield of 3D printed PDCs decreased from 58.4% to 30.2%, and the linear shrinkage increased from 27.2% to 40.3%. The bending strength of the LCD 3D printed specimen reached 61.5 ± 3.7 MPa. The low cost of precursor synthesis and equipment in this study points the way for the preparation of precursor non-oxide ceramic composites and can be conducive to the development and application of LCD 3D printing precursor ceramics. [ABSTRACT FROM AUTHOR]

In this study, nanosized Hf(C,N,O) ceramics were successfully prepared from a novel precursor synthesised by combining HfCl 4 with ethylenediamine and dimethylformamide. Subsequently, the carbothermal reduction of these Hf(C,N,O) ceramics into hafnium carbide was investigated. The Hf(C,N,O) ceramics comprised Hf 2 ON 2 and HfO 2 nanocrystals and amorphous carbon. Upon carbothermal reduction, conversion began at 1300 °C, when HfC first appeared, and continued to completion at 1500 °C, resulting in irregularly shaped crystallites measuring 50–150 nm. Upon increasing the dwelling time, the oxides were completely converted into carbides at 1400 °C. Furthermore, nitrogen was introduced into the reaction to catalyse the conversion of oxides into carbides considering the beneficial gas–solid reaction between CO and Hf 2 ON 2. We expect that the ceramics prepared in this study will be suitable for the fabrication of high-performance composite ceramics, with properties superior to those of current materials. [ABSTRACT FROM AUTHOR]

Aroma is an important indicator of fruit flavor, but mechanisms of aroma formation in strawberries (Fragaria spp.) during natural ripening are still not clear. In this study, aroma compounds in strawberry cultivars were analyzed using gas chromatography–mass spectrometry (GC–MS). Richly creamy strawberry cultivars in particular expressed high levels of vanillin acetate and coumarin (up-regulated by 12.6- and 9.8-fold, respectively), while the aroma-free cultivars were dominated by differential changes in terpenes and alcohols. Further research using liquid chromatography-mass spectrometry (LC-MS) and RNA-Seq indicated that the activation of the phenylpropanoid biosynthesis and alpha-linolenic acid metabolic pathways constituted the key to formation of aroma compounds in creamy strawberry cultivars. The results of this study not only provide a well-defined database to detect aroma compounds in different strawberry cultivars but also explore the underlying mechanisms of creamy aroma formation in strawberries. [Display omitted] • Terpenes were the major volatiles in aroma-free strawberry cultivars. • Vanillin acetate increased by 12.6-fold in creamy strawberry cultivars. • Amino acid precursors increased sharply during aroma formation. • Phenylpropanoid biosynthesis pathway was activated during aroma formation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Clean buffer solutions, in vivo , and in vitro are drastically different environments. • Electrochemically active interferents are present in cerebrospinal fluid. • Cerebrospinal fluid and culture media contain fouling molecules. • Fouling molecules decrease electrochemical reaction kinetics and sensor performance. • Kinetics of serotonin are not affected as much as monoamine neurotransmitters. Detection of neurotransmitters requires high sensitivity and temporal resolution, favoring electrochemical techniques for the sensing mechanism. However, electrochemical detection of amine neurotransmitters is highly dependent on electrode surface condition and thus, results obtained in clean buffer solutions are not directly applicable to the real measurement environment in vivo or in vitro. In these more complex electrolyte solutions, the presence of antioxidants and surface-adsorbing molecules drastically alters the redox characteristics of amine neurotransmitters, their precursors and metabolites. Accordingly, we surveyed their redox characteristics in the phosphate buffered saline (PBS), cerebrospinal fluid (CSF) and cell culture medium, with high-sensitivity electrodes made of single-walled carbon nanotube network. The concentration of surface-fouling molecules was lowest in the PBS and highest in the culture medium. Accordingly, electrochemical reaction kinetics were facile in the PBS and sluggish in the culture medium. Surprisingly, analyte molecular structure had much more importance in the CSF compared to other electrolytes, however the reaction kinetics remained to be generally slower in the CSF compared to when measured in the PBS. Whereas the CSF also contains L-Ascorbic acid and uric acid that are electrochemically active interfering molecules, they are either completely absent or can be omitted in the in vitro setting. On the contrast, the culture medium contains substantially higher concentration of surface-adsorbing molecules that causes more significant fouling of electrode and thus loss of sensitivity. As the in vitro brain-on-a-chip applications are rapidly being adopted, direct comparison of these different experimental settings was essential to understand their implications for electrochemical sensors. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Kozak sequence 'CGGACC' could significantly enhance gene expression. • Methanol assimilation was enhanced by targeting CAT-G4S-AOX1-per2 to peroxisomes. • Overexpression of pgk and PpgapN could enhance the supply of ATP and NADPH. • Overexpression of purF , adss, and PpcpdB could enhance the supply of adenosine. • The CO 2-eq of Pichia pastoris was significantly lower than Cordyceps militaris. Cordycepin, a nucleoside analog, is widely used in medicine and health products. However, the production of cordycepin from Cordyceps militaris faces the challenges of low productivity and high rate of greenhouse gas emissions. In this study, by optimizing the cordycepin biosynthesis pathway through promoter combination, Kozak sequence, and enzyme fusion, enhancing the methanol assimilation capacity in peroxisomes, adjusting the synthesis of NADPH and ATP, and combining the enhanced supply of adenosine and 3′-AMP, the cordycepin high-yield strain Pp29 was constructed, which produced 1551.44 mg/L cordycepin by shake-flask fermentation. In fed-batch fermentation, Pp29 achieved the highest yield (8.11 g/L, 67.64 mg/g DCW, and 1.35 g/L/d) to date in 10 L fermenter, and the CO 2-eq emissions were 1.9–17.3 times lower than C. militaris and other yeast systems. This study provide basis for Pichia pastoris to be used as chassis cell for synthesizing cordycepin and other nucleoside analogs by methanol as carbon source. [ABSTRACT FROM AUTHOR]

In this study, we report a chemical precursor-dependent dual effect of doping on the gas-sensing performance of metal oxide semiconducting materials. Our findings challenge the conventional notion that optimal doping consistently enhances gas-sensing properties. Acetate and nitrate salts were used as chemical precursors, lanthanum (La) was used as a dopant, and ZnO was used as a semiconducting material. All materials were synthesized under identical conditions by a two-step process involving dip coating and hydrothermal methods. Gas-sensing results demonstrated an improvement in the performance of the acetate-based doped film and a decline in that of the nitrate-based doped film compared to their respective pure counterparts. Among the produced sensors, 1 wt% La-doped ZnO sensor produced by the acetate precursor proved to be convenient for usages in real markets. It showed superior performance with a high response (62) at a relatively low operating temperature (150℃) towards 50 ppm of NH 3 gas. The sensor also demonstrated exceptional baseline stability, high short-term and long-term consistency, good selectivity, and strong tolerance to humidity (up to 70 RH%) with slightly slow adsorption-desorption rates. The dual effect was discussed with respect to dopant- and precursor-induced variations in structural and surficial characteristics, revealed by XRD, Raman, FESEM, AFM, and XPS. The discussion delved deeper into the role of chemical precursors on nanostructure growth and, for the first time, illuminated a temperature-dependent complex gas-sensing principle governed by the detected p-n shift of the semiconductor type of the sensing elements, confirmed by Hall effect. • Pure and La-doped ZnO films were hydrothermally produced by different precursors. • The dual effect of doping on gas-sensing properties of materials was discussed. • A semiconductor-type shift was observed, verified and explained. • The sensing performance was assessed via various structural and electrical parameters. • Temperature-dependent complex sensing process was elaborated based on p-n shift. [ABSTRACT FROM AUTHOR]

• Precursors derived in wastewater effluent dominated near the outfall. • Naturally occurring NDMA precursors dominated above and in as little as 6 km downstream of the outfall. • Wastewater-derived precursors may be less important to drinking water intakes than previously indicated. N -nitrosodimethylamine (NDMA) is a carcinogenic disinfection byproduct formed from reactions between dichloramine and organic nitrogen-containing precursors. It is unclear if NDMA precursors in surface water intakes originate in anthropogenic (i.e., wastewater) or natural sources. The Truckee River has a single point source release of treated wastewater effluent, making it an ideal system to study the relative importance of precursor sources. Three Lagrangian sampling events were conducted. NDMA formation potential (FP, a measurement of precursors) above the wastewater outfall indicated that the natural background of NDMA precursors was 2-28 ng/L. NDMA FP increased to 18-31 ng/L immediately downstream of the wastewater outfall, but decreased rapidly in a first order manner, and were not statistically different from the upstream samples in only ∼6 km. This suggests that the dominant source of NDMA precursors may be wastewater derived only near wastewater outfalls and deviates from the previous belief that wastewater-derived precursors are responsible for NDMA formation in drinking water sources located further downstream. Additionally, given the rapid loss of the wastewater precursors in this study, precursors which are slow to biodegrade/photolyze/adsorb to sediment are likely to be poor surrogates for the overall wastewater NDMA precursor pool. To understand temporal changes in the wastewater impact on environmental NDMA precursor loading, two 24-hour sampling events were conducted near (<3 km) the wastewater outfall and demonstrated that temporal changes in the NDMA precursors directly downstream of the wastewater outfall are directly linked to the wastewater flow contribution. [Display omitted] [ABSTRACT FROM AUTHOR]

This research pioneers the application of precursor concepts to preemptively identify and prevent aviation safety incidents using Machine Learning (ML). Airlines and governing organizations, such as the Federal Aviation Administration (FAA) in the United States, have been trying to prevent safety incidents during routine operations. However, this task is challenging due to the lack of timestep-wise event annotation in flights and the complexity involved in the timely identification of incidents prior to their occurrence. To address these issues, we propose a real-time precursor identification methodology combining Multiple-Instance Learning (MIL) and feature-based Knowledge Distillation (KD) learning. Our two-stage approach, involving deep MIL for labeling and a KD-based model for real-time warnings, demonstrates state-of-the-art performance and a time delay of 2.99ms using a dataset of 23,549 real flights. Further experiments using t-distributed Stochastic Neighbor Embedding (t-SNE) and occlusion method confirm our model's transparency, enabling the generation of reliable quantitative precursor scores and facilitating reasoning about the causes of safety incidents at the parameter level. Additionally, statistical analysis of precursors reveals varying evolution times for different safety events, which indicates that pilots have at least 8 s to react after receiving a warning. In conclusion, our research provides a theoretical foundation and technical support for the next generation of online risk warning systems, enhancing flight safety and offering a pathway towards more intelligent and secure flight operations. [ABSTRACT FROM AUTHOR]

In this paper, SiCO microsphere/polyvinyl silicon acetylene slurry was prepared for the first time with low viscosity and good rheological behavior. The dispersion of microspheres in the precursor resin and the UV-light curing performance of the slurry were investigated. After pyrolysis at 1000 °C, the properties of the three-dimensional (3D) printed samples were characterized. The introduction of SiCO microspheres reduced the specimen shrinkage of the pure precursor photosensitive resin used for additive manufacturing and improved their mechanical properties. When the addition of SiCO powder increased from 0 wt% to 10 wt%, the linear shrinkage decreased from 33 % to 26 %, and the flexural strength increased from 43.9 MPa to 79.8 MPa. This study realizes the preparation of Si-based composite materials through low-cost LCD additive manufacturing technology. It confirms the great potential of low-cost light-curing additive manufacturing to fabricate complex functional composite ceramic materials. [ABSTRACT FROM AUTHOR]

Polymer-derived silicon carbide (SiC) fibers show their merits of high-temperature resistance, oxidation resistance and corrosion resistance; and introducing certain amounts of hetero-elements into ceramic precursor could improve the properties of SiC fibers. Therefore, it is very important to accurately control the amount of introduced hetero-elements to optimize the functionalization of the target SiC fibers. The current method of hetero-element content determination in precursors is to directly adopt the method of hetero-element content in amorphous or microcrystalline ceramics. In contrast to ceramics, low molecule weight Al-contained precursors are easy to volatilize during the alkali fusion process. Moreover, the precursor digestion solution is more likely to produce silicic acid flocculent precipitation when the solution is treated after alkali fusion. These two main aspects seriously affect the detection accuracy of hetero-element content in precursors. In this work, taking polyaluminumcarbsilane (PACS), which is one of the most commonly used ceramic precursors, as a subject of research; and the effects of pretreatment conditions for accurate determination the Al element content within are investigated. The pretreatment method of air crosslinking for precursor, as well as pH value adjustment of digestion solution, is proposed; enabling the accurate detection of Al in PACS. The optimized pretreatment conditions are reached for obtaining the Al elements contents accordant with theoretical derived ones, showing that this method is accurate and reliable. This pretreatment strategy could be extended to other kinds of hetero-elements within precursors. [ABSTRACT FROM AUTHOR]

The polymer derived ceramics with complex shapes were prepared using the low-cost liquid crystal display (LCD) 3D printing technology. In this paper, we not only synthesized a liquid low-viscosity precursor with the photocurable group, but also provided a method to improve the forming precision and ceramic yield. The results showed that the introduction of KH570 could improve the curing accuracy, the ceramic yield. When the content of KH570 increased to 41 wt%, the curing shrinkage of the system decreased from 6.92% to 2.84%, the ceramic yield increased by 29.2%. Moreover, the mechanical properties of SiOC ceramics were studied and discussed. The bending strength of SiOC ceramic reached 44.2 MPa. And the ceramics after polishing were no cracks or other defects. This research demonstrates the huge potential for 3D - printed ceramics to become ubiquitous. [ABSTRACT FROM AUTHOR]

In this work, aluminum isopropoxide is used as the aluminum source, and acetylacetone (Hacac) is used as the ligand to synthesize a precursor, which can be used to prepare ultrafine Al 2 O 3 fibers. Fiber with excellent flexibility is obtained by electrospinning and subsequent heat treatment processes. The uniform diameter of the fiber is approximately 300–400 nm, and it has a compact structure and no surface defects, such as cracks and holes, the lack of which can prevent it from being damaged in the process of flexible behavior, such as folding in half. By analyzing the crystallization transformation process of the Al 2 O 3 precursor fibers, it is found that the precursor begins to transform from amorphous to γ-Al 2 O 3 at approximately 700 °C. After heat treatment at 1000 °C, it completely changed to α-Al 2 O 3 , which is 100–200 °C lower than the results reported in previous literature. Even after heat treatment at 1200 °C, the fiber still has good flexibility, which ensures its functional performance. In addition, the thermal conductivity of the prepared Al 2 O 3 fibers was only 0.318 W/m·K at 1000 °C, which can be used as a thermal insulation material in aerospace, high-temperature industries and other fields. [ABSTRACT FROM AUTHOR]

The knowledge of chloropropanediols (MCPD) fatty acid esters formation pathways is an important condition for these processing contaminants mitigation. This study aimed to assess the potential of a group of lipophilic environmental contaminants, polychlorinated alkanes, commonly known as chlorinated paraffins (CPs), to contribute to the formation of MCPD esters. Laboratory-scale model systems representing vegetable oils contaminated with both a technical mixture of short-chained CPs and individual short-chained CPs were designed and subjected to heat treatment (230 °C, 2 h) to simulate the deacidification and deodorisation processes. A substantial increase in MCPD content (up to 3.4 times the control levels) was observed in systems spiked with a technical mixture. MCPD formation seems to correlate very well with the concentration of CPs in these systems. Based on the generated data, we can conclude that the processing of vegetable oils contaminated with CPs might contribute to elevated concentrations of MCPD. • Model systems simulating heat treatment during vegetable oil refining were designed. • Chlorinated paraffins (CPs) may act as precursors of chloropropanediols (MCPDs). • 3-MCPDs levels increased up to 3.4 times with short-chained CPs (SCCPs) addition. • 3-MCPDs in heated oil strongly correlated with the amount of added SCCPs mixture. • Possible mechanisms of hydrogen chloride release from selected SCCPs were proposed. [ABSTRACT FROM AUTHOR]

Magnesium only-phyllosilicates such as serpentines (1:1) and stevensite (2:1) do exist in nature but are not abundant in pure form, whereas synthesized materials can ensure higher purity. Clay mineral hydrothermal synthesis is quite easy to perform, however, the condensation reactions leading to the formation of these phyllosilicates and their precursors are not well understood. Such knowledge would allow to predict the synthesis outcome in case of variation of experimental parameters. This study reports a chemical reaction mechanism explaining the parameters that are determining the type of the formed clay mineral. After a detailed characterization of each obtained phase, it is shown that pH has a lower effect compared to Mg to Si molar ratio. Our results show that above pH 10 the mechanisms of lizardite and stevensite formation are similar with the same elementary units, but that the type of material obtained depends on the availability in excess of magnesium (formation of lizardite) or silicon (formation of stevensite). [Display omitted] • Magnesium only-phyllosilicates formation mechanism starts with the same elementary units. • The excess of magnesium leads to the formation of lizardite (1:1 type). • The excess of silicon leads to the formation of stevensite/kerolite (2:1 type). [ABSTRACT FROM AUTHOR]

Heterocyclic aromatic amines (HAAs) are harmful byproducts in food heating. Therefore, exploring the prediction and generation patterns of HAAs is of great significance. In this study, genetic algorithm (GA) and support vector regression (SVR) are used to establish a prediction model of HAAs based on heating conditions, reveal the influence of heating temperature and time on the precursor and formation of HAAs in roast beef, and study the formation rules of HAAs under different processing conditions. Principal component analysis (PCA) showed that the effect on HAAs generation increases with the increase of heating temperature and time. The GA-SVR model exhibited near-zero absolute errors and regression correlation coefficients (R) close to 1 when predicting HAAs contents. The GA-SVR model can be applied for real-time monitoring of HAAs in grilled beef, providing technical support for controlling hazardous substances and intelligent processing of heat-processed meat products. • Revealed the effects of temperature and time on the formation of precursors and HAAs. • Studied the HAAs formation rules under different processing conditions in roast beef. • Established precise predictive model GA-SVR for HAAs based on heating conditions. • Model can controll harmful substances in processed meats and intelligent processing. [ABSTRACT FROM AUTHOR]

[Display omitted] • NPs@N-C was prepared by a simple and scalable autogenic pressure reaction. • Thickness of N-C layers was precisely controlled down to 1 nm. • Formation of NPs@N-C can be achieved regardless of nanoparticle types. • The Si@N-C exhibits capacity of 1311 mAg−1 and CE of 99.6% after 50 cycles. The carbon coating enables nanoparticles to withstand harsh environments, but achieving uniformity and scalability for their industrial use remains a challenge. In this work, we present a simple, controllable, and scalable strategy for one-pot coating with an N-doped carbon layer on the surface of various nanoparticles, including semiconductors, oxides, transition metals, and noble metals. Uniform coverage of the N-doped carbon layer was achieved through an autogenic pressure reaction of gaseous species derived from starting precursors in a closed reactor. The thickness of the coating layer could be precisely controlled by adjusting the amount of precursor, even down to the 1 nm level, because the precursor is completely consumed in the reactor without any loss. The crystallinity of the N-doped carbon layer could be modified by altering the coating temperature. Moreover, the results demonstrate that this coating process can be applied to different types of nanoparticles. Tests confirmed that nanoparticles retain their inherent nature while exhibiting more stable and enhanced properties after the N-doped carbon coating. We believe this approach offers a straightforward synthetic route for the design and application of nanoparticle coatings. [ABSTRACT FROM AUTHOR]

The mechanism of multi-step nucleation, which means that a precursor phase exists before the formation of the final crystal, has undergone significant development as an advanced strategy for the production of high-performance structural materials and the mitigation of carbon emissions. This study investigated the potential transformation of C–S–H precursors in water, 98 % RH, and high-temperature environments. The findings suggest that C–S–H precursors, produced by disrupting the two-step nucleation process, can transform in both aqueous and 98%RH conditions, while high temperature alone is insufficient to induce the transformation. The progress of the transformation under 98%RH was impeded by the limited mass transport resulting from the constrained formation of nano-crystalline C–S–H in adsorbed water on the external surface and the pores. This study emphasizes the crucial role of water in facilitating the transformation process, presenting potential opportunities for the nanoengineering of C–S–H-based composites and cementitious materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • The precursor components in the formation of HAAs have been investigated using UPLC-MS/MS. • The results confirmed the previously reported precursors and formation mechanisms of HAAs. • Some potential direct and indirect precursors for HAAs were discovered. The prevention and control of heterocyclic aromatic amines (HAA) formation to mitigate of potential risks to humans, can be achieved by targeting their precursors. In this study, the detailed roles of individual and excess component (20 common α-amino acids, creatine, creatinine, and glucose) on HAA formation in roasted beef patties were examined using UPLC-MS/MS. The results confirmed the reported classical precursors of HAAs. Some components regulated the competitive production of Norharman and Harman. Glycine (Gly) and glucose favored Norharman formation, while cysteine (Cys) and phenylalanine (Phe) for Harman. Serine (Ser) and threonine (Thr) were identified as potential precursors for IQx-type HAAs. Interestingly, methionine (Met), Gly, Thr, Cys, alanine (Ala), and Ser were revealed as more targeted underlying precursors for 1,6-DMIP and 1,5,6-TMIP, and the formation mechanism was inferred. Furthermore, Pro, Leu, His, Ile, Lys and Asp were considered as great inhibitors for HAAs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two novel tungsten complexes (RCp)W(CO) 2 (η3-2- tert -butylallyl) were synthesized. • Precursor in liquid phase could be obtained by tuning the coordinated alkyl chain. • Two precursors exhibit favorable thermal stability and volatility for thin film deposition. Two organometallic tungsten complexes (RCp)W(CO) 2 (η3-2- tert -butylallyl) (R = methyl or ethyl, Cp = cyclopentadienyl) as precursors capable of growing tungsten-containing thin films, are constructed bearing heteroleptic ligand system. The syntheses adopt a rationally designed approach excluding the use of extreme conditions and involving facile purification procedures. The two complexes are authenticated by nuclear magnetic resonance (NMR) and elemental analysis, as well as Fourier transform-infrared (FT-IR) spectroscopy. Thermal property evaluations, including thermogravimetric and vapor pressure tests, reveal favorable thermal stability and volatility which are essential for a typical ALD process. It is noteworthy that both precursors possess relatively low-melting point and specifically, the one bearing ethyl-Cp group is in liquid phase at room temperature. Such design concept of heteroleptic ligand system and substructure tuning pave the way to develop liquid precursors which are imperative demand in microelectronic industry. [ABSTRACT FROM AUTHOR]

Polymeric precursors with refractory metal in the main chain while still possess meltable/soluble characteristics are highly desired for ultra-high temperature ceramics (UHTCs). Herein, we proposed a stepwise synthesis of polyzirconosilane (PZCS) with Zr-C-Si-N polymeric chain. The reaction mechanism was discussed based on the frontier molecular orbital theory and atom transfer radical polymerization, which was initiated and propagated by a low oxidation state active specie of Cp 2 Zr(II). The PZCS precursor has excellent soluble and meltable properties with a softening point of 80.8 ~ 89.2 oC, which could be spun into green fibers by melt spinning technique. The ceramization process of PZCS was studied, and the resulted SiZrNC multinary ceramics were composed of ZrC/SiC nanocrystals embedded by graphitized carbon phase. The excellent mouldable properties, oxygen-free compositions and high Zr content of PZCS make it an ideal precursor for the preparation of UHTCs matrixes and fibers. • In this work, the conclusions and innovations are as follows: • A novel polymeric precursor with Zr-C-Si-N main chain structure was synthesized through a two-step method using Cp 2 ZrCl 2 , Mg, and [ClCH 2 Si(CH 3) 2 ] 2 NH as raw materials. The low oxidation state active specie of Cp 2 Zr(Ⅱ) with two semi-filled outer orbits was obtained by the reaction of Cp 2 ZrCl 2 with Mg, which played an important role in the reaction. • The synthesized PZCS precursor exhibited excellent soluble and meltable properties with a softening point of 80.8 ~ 89.2 oC, which could be spun into green fibers by melt spinning. In addition, the green fibers can well preserve the organic structure and morphology when placed in air for a few hours. • The pyrolysis of PZCS precursor was studied in detail, and its ceramic yield was 50.82 wt%. Thermal treatment of the prepared single-source precursor resulted in SiZrNC composites with ZrC/SiC nanocrystals dispersed in graphitized carbon matrix. [ABSTRACT FROM AUTHOR]

(B,N)-codoped TiO 2 was prepared by the oxidation method using TiBN powder as a precursor. The oxidation of TiBN powder particles started with the surface, producing a high-Ti low-O compound Ti 2 O 3. Meanwhile, accompanied by the migration and oxidation of B, the oxidative process gradually extended towards the interior, giving rise to the formation of (B,N)-codoped TiO 2. XRD analysis revealed that, in oxidative products, the residual TiBN phase was structurally similar to Ti 4 N 3 B 2 , suggesting that Ti had diffused and migrated outwards from TiBN. On this basis, an oxidative model was built for TiBN particles. The oxidation of TiBN consisted of two processes: chemical reaction (TiBN→Ti 2 O 3 →TiO 2) and organizational structure evolution (TiBN→Ti 4 N 3 B 2). The prepared TiO 2 was dominated by rutile form and also contained small amounts of anatase and residual TiBN. (B,N) Codoping increased the lattice parameter of rutile TiO 2. Organizational structure was found to be related to the parameters of the oxidative process. Pure rutile TiO 2 could be obtained from TiBN powder under 800°C + 2h oxidative treatment, and the interplanar spacings of its (110), (101), (211), and (111) planes were 0.324877 nm, 0.24875 nm, 0.16874 nm, and 0.21873 nm, respectively. These interplanar spacings were greater than the interplanar spacings of TiO 2 produced through the oxidation of TiN under equal conditions, which was attributable to (B,N) codoping in TiO 2. According to direct observations by high-resolution transmission electron microscopy (HRTEM), the organizational structure of TiO 2 particles demonstrated the fine size and elliptical boundary and contained amorphous layers. This study offers a new approach to (B,N) codoping in TiO 2. The (B,N)-codoped TiO 2 with high photocatalytic efficiency obtained in this study can be applied in environmental and energy fields. [ABSTRACT FROM AUTHOR]

Nano size ZrC powder was prepared by liquid polymeric precursor method. Zirconium n-butoxide (Zr(OnBu) 4) and benzoylacetone (BA) were mixed directly with different molar ratios to synthesize transparent liquid zirconium carbide single-source precursors. The carbon content in the precursor could be changed by adding different amount of BA. X-ray pure ZrC was obtained when the molar ratio of BA/Zr(OnBu) 4 was 4.6:1. The viscosity of the precursor was very low (<8 mPa s) without the addition of solvents. Zirconium carbide powders were fabricated by the pyrolysis at 800 °C in argon and subsequent heating at various temperatures in vacuum for carbothermal reduction reaction. The pyrolysis behavior, phase composition and transformation, and microstructure of the as-fabricated ZrC powders were analyzed. The gases of CH 4 , CO and CO 2 released due to decomposition and evaporation of the organic component and transformation from ZrO 2 to ZrC during pyrolysis resulted in total 60–70% mass loss. The average grain size of the synthesized X-ray pure ZrC powders was less than 30 nm. Meanwhile, the pyrolysis mechanism of nano zirconium carbide powder was deduced. [ABSTRACT FROM AUTHOR]

Disinfection by-products (DBPs) formed during water disinfection has drawn significant public concern due to its toxicity. Since the first discovery of the trihalomethanes in 1974, continued effort has been devoted on DBPs worldwide to investigate the formation mechanism, levels, toxicity and control measures in drinking water. This review summarizes the main achievements on DBP research in China, which included: (1) the investigation of known DBP occurrence in drinking water of China; (2) the enhanced removal of DBP precursor by water treatment process; (3) the disinfection optimization to minimize DBP formation; and (4) the identification of unknown DBPs in drinking water. Although the research of DBPs in China cover the whole formation process of DBPs, there is still a challenge in effectively controlling the drinking water quality risk induced by DBPs, an integrated research framework including chemistry, toxicology, engineering, and epidemiology is especially crucial. [Display omitted] [ABSTRACT FROM AUTHOR]

Effects of carbon source in single-source ZrC-based liquid precursors on the properties of the precursors and precursor-derived nano ZrC powders were investigated. The liquid precursors were prepared by directly blending and heating zirconium n-butoxide with either 2,4-pentanedione, benzoyl acetone or 1,3-diphenyl-1,3-propanedione additives which have the same chemical composition and structure except for the number of benzene rings (0, 1 and 2, respectively) in order to control the carbon content in the precursors. The ceramic yield of the precursor decreased as the number of benzene rings in the precursors increased. The stability of the precursors in air and the carbon content of the ceramic powder increased when using 1,3-diphenyl-1,3-propanedione additive. X-ray pure nano zirconium carbide powders with ultra-fine size (30 nm), isotropic shape and homogeneous particle size distribution were synthesized from the liquid precursors containing two benzene rings in the structure. Compared with ZrC powders derived from the precursors containing zero or one benzene ring, the powder from the precursor containing two benzene rings was finer and more homogeneous in size distribution. [ABSTRACT FROM AUTHOR]

Polycrystalline aluminum oxynitride (AlON) powders have been prepared by the carbothermal reduction nitridation of amorphous precursor obtained by solution combustion synthesis (SCS). Firstly, a mixed precursor of amorphous transition alumina and incompletely combusted organic matter has been combustion synthesized of a mixed solution of aluminum nitrate, urea and glucose. Then the pure phase AlON powders with D 50 = 0.846 μm can be prepared by calcining the SCS precursor at 1700 °C for only 10 min. The influences of different urea/aluminum nitrate nonahydrate ratio, calcining temperature and holding time on the properties of products have been discussed in detail. The research can provide a valuable reference for the efficient synthesis of AlON powders. [ABSTRACT FROM AUTHOR]

Disinfection is an indispensable water treatment process to kill pathogens in water and prevent water-borne diseases. However, the disinfection by-products generated in the process have become the main cause of threats to human health and the ecological environment. Many studies have shown that removing the precursors of disinfection by-products is currently one of the most effective methods to reduce the production of disinfection by-products. Ultraviolet-coupled advanced oxidation processes can generate strong oxidizing free radicals through ultraviolet light activation to efficiently remove disinfection by-product precursors. It makes up for the deficiencies of traditional oxidation technology, has important significance in reducing the generation potential of disinfection by-products, and improving water quality conditions, with broad development prospects. This paper reviews the mechanisms and advances of several UV-coupled advanced oxidation processes for the treatment of disinfection by-product precursors, UV/ozone (UV/O3), UV/hydroperoxide (UV/H2O2), UV/persulfate (UV/PS), UV/chlorine (UV/Cl2) included. The treatment effects, advantages, and disadvantages of various advanced oxidation processes are compared, moreover, the future research directions and problems to be solved for the removal of disinfection by-products and precursors are proposed to promote the achievement of practical engineering application of UV coupled advanced oxidation processes. [ABSTRACT FROM AUTHOR]

Sulfidized nanoscale zero-valent iron (S-nZVI) showed excellent removal capacity for cadmium (Cd) in aqueous phase. However, the remediation effects of S-nZVI on Cd-contaminated sediment and its interactions with microorganisms in relation to Cd fate remain unclear. The complexity of the external environment posed a challenge for Cd remediation. This study synthesized S-nZVI with different S and Fe precursors to investigate the effect of precursors and applied the optimal material to immobilize Cd in sediments. Characterization analysis revealed that the precursor affected the morphology, Fe0 crystallinity, and the degree of oxidation of the material. Incubation experiments demonstrated that the immobilization efficiency of Cd using S-nZVI Fe 3+ +S 2- (S/Fe = 0.14) reached the peak value of 99.54%. 1% and 5% dosages of S-nZVI significantly reduced Cd concentration in the overlying water, DTPA-extractable Cd content, and exchangeable (EX) Cd speciation (P < 0.05). Cd leaching in sediment and total iron in the overlying water remained at low levels during 90 d of incubation. Notably, each treatment maintained a high Cd immobilization efficiency under different pH, water/sediment ratio, organic acid, and coexisting ion conditions. Sediment physicochemical properties, functional bacteria, and a range of adsorption, complexation and precipitation of CdS effects dominated Cd immobilization. [Display omitted] • Precursors affect the structures and surface chemistry of S-nZVI. • The immobilization efficiency of S-nZVI material for Cd in sediment was up to 99.54%. • S-nZVI kept high immobilization efficiency under various environmental factors. • Fe-reducing bacteria and sulfate-reducing bacteria were correlated with the Cd fate. • Adsorption, complexation and precipitation were the immobilization mechanisms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel spectrophotometric methods for analysis of new mixture with chemical precursor. • Smart HPTLC method for analysis of new mixture with chemical precursor. • Evaluation of the greenness profile of the developed methods. • The developed methods are economic, energy saving and ecofriendly methods. • Green comparison between the developed methods and reported one. Recently, Countless people have become affected as a result of the Covid-19 crisis. Even after recovery, COVID-19 can lead to respiratory difficulties and lung impairment consequently; bacterial infections have a good possibility of infiltrating our respiratory system due to reduction in respiratory immunity. Therefore, the importance of the chosen mixture of doxycycline and ambroxol becomes clear here curing bacterial illnesses invade respiratory tract. The ternary blend of (DOX) doxycycline hyclate, (AMB) ambroxol hydrochloride, (IMP) chemical ambroxol precursor, and pharmacopeial impurity was quantified using four contemporary, selective, and straightforward methods. Method (I) was area under the curve spectrophotometric method (AUC), where zero order absorption spectra were used for calculating the area under the curve of AMB, IMP, and DOX in ranges of 205–219, 222–245, and 264–290 nm, respectively. Each component's absorptivity values (a) at the chosen area were computed. Method (II) was differential dual wavelength (DDW), where upon collecting the first derivative spectra of AMB, IMP, and DOX, amplitudes at 252–263.4, 236–246.6, and 388.8–420 nm were subtracted, consecutively. Method (III) the mean centering of ratio spectra spectrophotometric method (MCR), peak to peak amplitudes on these resulted spectra were measured at (258.2 and 258.4 nm) for AMB, (264.4 and 264.6 nm) for IMP, and at (230.4 and 230.6 nm) for DOX. In addition, method (IV) HPTLC using a stationary phase made of silica gel HPTLC plates that had been pre-treated with 0.27 M di-sodium-EDTA (pH 9 with 21 % sodium hydroxide). The platform is developed using the eluent of ethyl acetate, acetone, distilled water, and acetic acid (9:2:0.7:0.55, by volume) and scanning by employing ultraviolet light regarding AMB and IMP at 254 nm while DOX at 380 nm. For validating the developed procedures, ICH principles were adhered to. The proposed methods were successful in studying dosage form containing investigated substances. The developed techniques' greenness features were assessed using a variety of greenness parameters, and an environmental evaluation comparison between the current methods and the reported one was done. Obtained methods' statistical analyses were also performed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ru/TiO 2 catalysts with 1.1 nm (small), 2.9 nm (medium) and 5.2 nm (large) Ru particles were successfully synthesized. • The medium Ru particles on TiO 2 exhibited the best CO 2 methanation activity. • The medium Ru particles exhibited the best redox properties compared with small and large Ru particles. • The medium Ru particles exhibited a moderate ability to activate CO 2 , resulting in the best CO 2 methanation activity. The influence of metal particle size over heterogeneous catalysts on the catalytic performance has always been an interesting subject due to its significance from both fundamental and practical perspectives. In this work, we regulated the synthesis of TiO 2 by the hydrolysis of different titanium precursors, and as-prepared TiO 2 supports were employed to load Ru with impregnation method. Interestingly, we synthesized three Ru-TiO 2 catalysts with different Ru particle sizes of 1.1, 2.9 and 5.2 nm. The Ru-TiO 2 catalysts were next tested for CO 2 hydrogenation reaction, the results show that the medium Ru particles on TiO 2 exhibited the best CO 2 methanation activity. Based on the characterizations, we observed that the medium Ru particles exhibited the best redox properties compared with small and large Ru particles, which was beneficial to the H 2 dissociation; in addition, the medium Ru particles exhibited a moderate ability to activate CO 2 , resulting in the most favorable formation and decomposition of bidentate bicarbonate. Consequently, the Ru-TiO 2 catalyst with medium Ru particles showed the highest activity for CO 2 methanation. This study provides a new method to prepare Ru-TiO 2 catalysts with different Ru sizes and also presents an understanding of Ru particle size effects on CO 2 hydrogenation. [ABSTRACT FROM AUTHOR]

Alkali-activated binders are considered a low carbon alternative for cement. However, it is important to address the carbon dioxide emission and high cost associated with the currently used commercial activators. Hence, recent studies focus on developing sustainable, low-cost alternative activators. Although rice husk ash derived activator is a potential alternative to commercial activators, studies on rice husk ash derived activator is highly limited. Hence, the present study focuses on the performance evaluation of alkali-activated binders using rice husk ash derived activators. The effect of activators is studied for bagasse based binary and ternary alkali-activated binders. Moreover, the influence of rice husk ash derived activators is meticulously compared with commercial sodium silicate derived activators. In addition, the influence of heat and ambient curing was also investigated. Mechanical, durability and microstructural properties of bagasse ash based alkali-activated binders were assessed. Bagasse ash-fly ash based binders activated using rice husk derived activators yielded the maximum compressive strength. However, bagasse ash-slag based binders with commercial sodium silicate activators exhibited higher performance than rice husk ash derived activators. In the case of bagasse ash-slag-fly ash based ternary binders, specimens activated using the rice husk ash derived activator had better performance than specimens activated using the other conventional activators. Even though the addition of 10% bagasse ash increased the performance of fly ash based binders, the incorporation of bagasse ash reduced the performance of slag and ternary alkali-activated binders. The results also showed that the rice husk ash based activator is a feasible alternative for the activation of bagasse based precursors to generate desirable mechanical strengths and durability. [Display omitted] • Sugarcane bagasse ash based binary and ternary alkali activated binders are studied. • Influence of rice husk ash derived activator on bagasse ash based AAB is evaluated. • Performance of RHA derived activators is compared with conventional activators. • Better performance of SCBA-fly ash based AAB is stated for RHA derived activators. • RHA derived activator is more beneficial for ternary AAB than commercial activators. [ABSTRACT FROM AUTHOR]

The control of ethyl acetate emissions from fermentation and extraction processes in the pharmaceutical industry is of great importance to the environment. We have developed three Mn 2 O 3 catalysts by using different Mn precursors (MnCl 2 , Mn(CH 3 COO) 2 , MnSO 4), named as Mn 2 O 3 -Cl, -Ac, -SO 4. The tested catalytic activity results showed a sequence with Mn precursors as: Mn 2 O 3 -Cl > Mn 2 O 3 -Ac > Mn 2 O 3 -SO 4. The Mn 2 O 3 -Cl catalyst reached a complete ethyl acetate conversion at 212℃ (75℃ lower than that of Mn 2 O 3 -SO 4), and this high activity 100% could be maintained high at 212℃ for at least 100 hr. The characterization data about the physical properties of catalysts did not show an obvious correlation between the structure and morphology of Mn 2 O 3 catalysts and catalytic performance, neither was the surface area the determining factor for catalytic activity in the ethyl acetate oxidation. Here we firstly found there is a close linear relationship between the catalytic activity and the amount of lattice oxygen species in the ethyl acetate oxidation, indicating that lattice oxygen species were essential for excellent catalytic activity. Through H 2 temperature-programmed reduction (H 2 -TPR) results, we found that the lowest initial reduction temperature over the Mn 2 O 3 -Cl had stronger oxygen mobility, thus more oxygen species participated in the oxidation reaction, resulting in the highest catalytic performance. With convenient preparation, high efficiency, and stability, Mn 2 O 3 prepared with MnCl 2 will be a promising catalyst for removing ethyl acetate in practical application. [Display omitted] [ABSTRACT FROM AUTHOR]

The ion exchange processes and phase formation were studied by varying the properties of 1D barium titanate nanostructures. Temperature-, time- and alkalinity-dependent experiments were performed to study the BaTiO 3 formation mechanism involving the generation of chemical sites which induced in situ transformation and dissolution-precipitation reactions occurring in a hydrothermal treatment procedure. As a result of the hydrothermal synthesis, BaTiO 3 nano- and microrods with surface nanomaces and nanoparticle aggregates were formed in the temperature range of 160–210 °C, alkalinity range of 0.025–0.15 M and time range of 45–90 min. X-ray diffraction analysis revealed a significant increase in BaTiO 3 material purity with increasing alkalinity from 0.025 to 0.15 M, even after a synthesis time of 45 min. In turn, Raman spectroscopy results showed that an increase in the synthesis time allowed not only BaTiO 3 purity improvement, but also its phase composition control. The tetragonal phase of BaTiO 3 was clearly observed after 6 h of hydrothermal synthesis at 210 °C and various alkalinities (from 0.025 to 0.15 M), while 45 and 90 min resulted in a mixture of cubic or tetragonal phases. Transmission electron microscopy demonstrated that BaTiO 3 nanoparticles consisted of mainly tetragonal phases or a mixture of cubic and tetragonal phases, while BaTiO 3 nano-/microrods preferably had cubic phases. Thus, variation of the temperature, time and alkalinity upon hydrothermal synthesis allowed the formation of BaTiO 3 nano- and microstructures with different morphologies and phase compositions for diverse applications from biomedicine to microelectronics. [ABSTRACT FROM AUTHOR]

Behavior of spacecraft structural materials under the high-velocity impact should be thoroughly investigated due to the constant threat of collision with space debris and meteoroids. Syntactic foams are perspective lightweight composite materials for spacecraft protection capable to attenuate shock waves. The shock response of highly filled syntactic foam to uniaxial planar impact loading was investigated using a powder gun facility and a laser velocimeter technique. The studied 0.64 g/cm3 foam consisted of an epoxy matrix filled with 55% volume fraction of glass microspheres. Measured wave profiles demonstrate the complex two-wave configuration associated with formation of precursor and compaction waves. Hugoniot and strain-rate data for the syntactic foam are presented in the stress range of 0.28–0.7 GPa. The Hugoniot elastic limit are determined to be 0.12 GPa, which implies that a precursor cannot be neglected in shocked state calculations in the studied loading regime. The density of the foam decreases with increasing loading stress due to thermal effects. The effect of sample thickness on wave fronts, wave velocities and precursor amplitudes is described. Precursor waves did not reach stable states in the experiments. • Syntactic foams are suggested as materials for spacecraft protection. • Shock properties of syntactic foam are investigated under high-velocity impact. • Two-wave structure are observed in shock loaded syntactic foams. • Density of highly filled syntactic foam decreases with increasing shock stress. • Unsteady state of precursor waves is observed. [ABSTRACT FROM AUTHOR]

Nano-scale powder of Magnesium (Mg) is found to play the dual role of catalyst and precursor with Boron-10 (10B) in the synthesis of Magnesium diboride nanoparticles (Mg10B 2 NPs) at 800 °C. Catalytically, Mg softens and melts enriched Boron at a relatively lower temperature than its actual boiling point. As a precursor, it reacts with enriched Boron and forms the Mg10B 2 compound. The nano-size catalyst and precursors help to grow the as-formed Mg10B 2 compound in the form of nanoparticles. The shape or morphology of the synthesized Mg10B 2 NPs is revealed via field emission scanning electron microscopy (FESEM). Energy dispersive x-ray (EDX) spectroscopy has been performed to spot the elemental composition, whereas, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) are used to verify the composition and study the phase of the synthesized particles. [ABSTRACT FROM AUTHOR]

It is widely accepted that the tricarboxylic acid (TCA) cycle is a critical partner for gluconeogenesis (GNG) in hepatocytes. Although researchers in the 1950s showed, using radiolabeled long-chain fatty acids, that acetate derived from fatty acid β-oxidation contributes carbon to glucose, fatty acids are not included on lists of gluconeogenic precursors in many textbooks of biochemistry and nutritional biochemistry. Here, by following the flow of carbon atoms through the mitochondrial TCA cycle and into cytosolic GNG, it is shown that carbons in acetyl-CoA derived from fatty acid β-oxidation will be found in glucose. Specifically, it is evident that, after the condensation of acetyl-CoA and oxaloacetate (OAA) to make citrate at the start of the TCA cycle, the 2 carbons lost from the cycle as carbon dioxide come from OAA, not acetyl-CoA. Carbons from acetyl-CoA are retained as the cycle progresses toward malate, and when malate exits the mitochondrion for GNG, carbons that originated in acetyl-CoA and OAA are found to contribute equally to glucose. With influx of other critical precursors into the TCA cycle and efflux of malate into the cytosol for GNG, the TCA cycle is in balance. During fasting-induced GNG, there is a net gain of glucose in glucogenic cells; however, the fact that there is no net gain in the TCA cycle is irrelevant as far as precursors are concerned. Given the physiological importance of fat as a source of reserve energy, and knowing that some cell types rely on glucose as their primary supplier of energy, a role for fatty acids in glucose production aligns both with intuition and with evidence provided by a careful look at the biochemistry and older isotope studies. Hopefully, subsequent editions of textbooks will list fatty acids among the gluconeogenic precursors. [ABSTRACT FROM AUTHOR]

Although studies have shown that severe anhedonia in patients with major depressive disorder (MDD) is associated with poor treatment outcomes, the biological mechanism of this feature is unclear. The aim of this study was to investigate the dysfunction of brain-derived neurotrophic factor (BDNF) metabolism, measured by the ratio of mature BDNF to precursor-BDNF, in MDD patients with severe anhedonia. We measured plasma levels of mature BDNF (mBDNF), precursor-BDNF (proBDNF), tissue plasminogen activator (tPA) and tropomyosin-related kinase B (trkB) in outpatients with MDD with anhedonia (n = 26), outpatients with MDD without anhedonia (n = 29) and age- and sex-matched healthy controls (HCs, n = 38) by enzyme-linked immunosorbent assay kits, and we calculated the ratio of mBDNF to proBDNF (M/P). We compared these biological determinants among the three groups and explored the interrelationships between anhedonia severity and BDNF metabolism. The levels of mBDNF, proBDNF, and tPA and the ratio of M/P were identified with highly significant differences among the three groups. Compared with MDD patients without anhedonia and healthy controls, MDD patients with anhedonia showed higher level of the ratio of M/P, and it was positively associated with the SHAPS scores in MDD patients. Compared to healthy controls, the plasma tPA concentrations were higher in MDD patients with anhedonia but were not different from those in MDD patients without anhedonia. These results provide novel evidence regarding the relationship between anhedonia and plasma BDNF metabolism. The hypermetabolism of BDNF may be a function of anhedonia rather than other characteristics in MDD. [ABSTRACT FROM AUTHOR]