bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of Small-Scale Hydrogen Production with Membrane Reactors
Authors: Ongis Michele , Di Marcoberardino Gioele , Baiguini Mattia , Gallucci Fausto , Binotti Marco
Published: March 2023

In the pathway towards decarbonization, hydrogen can provide valid support in different sectors, such as transportation, iron and steel industries, and domestic heating, concurrently reducing air pollution. Thanks to its versatility, hydrogen can be produced in different ways, among which steam reforming of natural gas is still the most commonly used method. Today, less than 0.7% of global hydrogen production can be considered low-carbon-emission. Among the various solutions under investigation for low-carbon hydrogen production, membrane reactor technology has the potential, especially at a small scale, to efficiently convert biogas into green hydrogen, leading to a substantial process intensification. Fluidized bed membrane reactors for autothermal reforming of biogas have reached industrial maturity. Reliable modelling support is thus necessary to develop their full potential. In this work, a mathematical model of the reactor is used to provide guidelines for their design and operations in off-design conditions. The analysis shows the influence of temperature, pressures, catalyst and steam amounts, and inlet temperature. Moreover, the influence of different membrane lengths, numbers, and pitches is investigated. From the results, guidelines are provided to properly design the geometry to obtain a set recovery factor value and hydrogen production. For a given reactor geometry and fluidization velocity, operating the reactor at 12 bar and the permeate-side pressure of 0.1 bar while increasing reactor temperature from 450 to 500 °C leads to an increase of 33% in hydrogen production and about 40% in HRF. At a reactor temperature of 500 °C, going from 8 to 20 bar inside the reactor doubled hydrogen production with a loss in recovery factor of about 16%. With the reactor at 12 bar, a vacuum pressure of 0.5 bar reduces hydrogen production by 43% and HRF by 45%. With the given catalyst, it is sufficient to have only 20% of solids filled into the reactor being catalytic particles. With the fixed operating conditions, it is worth mentioning that by adding membranes and maintaining the same spacing, it is possible to increase hydrogen production proportionally to the membrane area, maintaining the same HRF.
A Note on Vestigial Osmotic Pressure
Authors: Wu Hao , Ou-Yang Zhong-Can , Podgornik Rudolf
Published: March 2023

Recent experiments have indicated that at least a part of the osmotic pressure across the giant unilamellar vesicle (GUV) membrane was balanced by the rapid formation of the monodisperse daughter vesicles inside the GUVs through an endocytosis-like process. Therefore, we investigated a possible osmotic role played by these daughter vesicles for the maintenance of osmotic regulation in the GUVs and, by extension, in living cells. We highlighted a mechanism whereby the daughter vesicles acted as osmotically active solutes (osmoticants), contributing an extra vestigial osmotic pressure component across the membrane of the parent vesicle, and we showed that the consequences were consistent with experimental observations. Our results highlight the significance of osmotic regulation in cellular processes, such as fission/fusion, endocytosis, and exocytosis.
Enhancing Hydrogen Sulfide Detection at Room Temperature Using ZIF-67-Chitosan Membrane
Authors: Ali Ashraf , Alzamly Ahmed , Greish Yaser E. , Alzard Reem H. , El-Maghraby Hesham F. , Qamhieh Naser , Mahmoud Saleh T.
Published: March 2023

Developing new materials for energy and environment-related applications is a critical research field. In this context, organic and metal–organic framework (MOF) materials are a promising solution for sensing hazardous gases and saving energy. Herein, a flexible membrane of the zeolitic imidazole framework (ZIF-67) mixed with a conductivity-controlled chitosan polymer was fabricated for detecting hydrogen sulfide (H2S) gas at room temperature (RT). The developed sensing device remarkably enhances the detection signal of 15 ppm of H2S gas at RT (23 °C). The response recorded is significantly higher than previously reported values. The optimization of the membrane doping percentage achieved exemplary results with respect to long-term stability, repeatability, and selectivity of the target gas among an array of several gases. The fabricated gas sensor has a fast response and a recovery time of 39 s and 142 s, respectively, for 15 ppm of H2S gas at RT. While the developed sensing device operates at RT and uses low bias voltage (0.5 V), the requirement for an additional heating element has been eliminated and the necessity for external energy is minimized. These novel features of the developed sensing device could be utilized for the real-time detection of harmful gases for a healthy and clean environment.
Buckling of Bisegment Pressure Hulls Fabricated through Free Bulging
Authors: Teng Yun , Zhang Jian , Wang Feng
Published: March 2023

This study explored the buckling performance of bi-segment pressure hulls under external pressure. We fabricated bi-segment pressure hulls from bi-segment cylindrical preforms by using free bulging. The cylindrical preforms had a nominal thickness of 0.95 mm, nominal radius of 51 mm, and nominal height of 242 mm. Six bi-segment pressure hulls were hydrostatically and externally pressurised into buckling. Experimental results revealed that the maximum buckling load of the bi-segment pressure hulls was increased by 36.75% compared with that of the bi-segment cylinders. In addition, we performed a nonlinear finite element analysis to determine the bulging and buckling modes of the hulls. We noted that the nonlinear analysis results exhibited good agreement with the experimental data.
Surface Evolution of Vermicular Cast Iron in High Frequent Cyclic Plasma and Different Facial Cooling Airflows
Authors: Liu Lei , Zhao Ke , Zhang Haijun , Tang Chengwei , Han Qinxin , Chen Jiajia , Tao Dong , Yang Zhong
Published: March 2023

The surface evolution of vermicular cast iron in a high frequent cyclic plasma and facial cooling airflow was studied to understand the behavior and mechanism in different cooling conditions under a unique thermal shock environment. Results indicated that both the mass and linear loss presented titled inverted V-shaped relationships with the flux of the cooling airflow, while the change in roughness decreased continuously. As the cooling airflow rose, the eroded zone was reduced, the iron oxides lessened, and fluctuation of the surface temperature weakened. In combination with the thermodynamic calculations and thermal analysis, it was confirmed that the oxidation and mechanical erosion had contrary tendencies with the rising flux in the facial cooling airflow. The transformation of the dominant factor from oxidation to peeling off by thermal stress and scouring resulted in the evolution of mass and thickness. The surface oxides dominated the change in the roughness.
Mechanical Properties and Tensile Failure Mechanism of Friction Stir Welded 2219-T6 and 5A06-H112 Joints
Authors: Gu Jinghong , Xue Wei , He Diqiu
Published: March 2023

Friction stir welding was employed to weld dissimilar 2219/5A06 Al alloys in this work. The influences of alloy positioning on the mechanical properties and fracture behavior of the joints were studied via fracture morphology observation and microstructural analysis. The results show that the difference in the plastic flow and thermal field in the welding process is caused by different basic material configurations, which results in the formation of a free strengthening phase zone and microstructural heterogeneity in the joint. The low-hardness texture component caused by the free strengthening phase zone and microstructural heterogeneity becomes crack initiation, and a crack tends to propagate along the grain boundaries. Finally, when the stronger 2219-T6 alloy was placed on the advancing side, the joints had better tensile properties. The average tensile strengths of the 2A5R and 5A2R joints can reach 79.8% (343 MPa) and 78.4% (337 MPa) of the 2219 base material, respectively.
Fatigue Behavior and Fracture Features of Ti-15Mo Alloy in β-, (α + β)-, and Ultrafine-Grained Two-Phase States
Authors: Gatina Svetlana A. , Polyakova Veronika V. , Modina Iuliia Mikhailovna , Semenova Irina P.
Published: March 2023

The influence of the ultrafine-grained structure formed by equal-channel angular pressing via the “Conform” scheme on the fatigue behavior of metastable β-alloy Ti-15Mo has been studied. It is shown that the alloy with a two-phase ultrafine-grained structure achieved the best mechanical properties and enhanced fatigue endurance limit (up to 710 MPa on the basis of 107 cycles) due to the total contribution of grain boundary, dislocation, and phase strengthening mechanisms. A fractographic analysis of the fracture surface of samples after fatigue tests showed the features of fatigue crack propagation depending on the type of alloy microstructure. The general and distinctive features of fatigue failure of alloy samples in the initial coarse-grained (α + β)-, single-phase coarse-grained β-, and ultrafine-grained (α + β)-states are revealed. In all of the samples, a fatigue crack nucleated on the surface and propagated downward, i.e., perpendicular to the direction of the applied pressures. It is shown that fracture surfaces of the ultrafine-grained samples had a high roughness and were characterized by the presence of a large number of secondary cracks, as compared to the coarse-grained analogues.
A Comprehensive Review on the Conventional and Non-Conventional Machining and Tool-Wear Mechanisms of INCONEL®
Authors: Pedroso A. F. V. , Sousa V. F. C. , Sebbe N. P. V. , Silva F. J. G. , Campilho R. D. S. G. , Sales-Contini R. C. M. , Jesus A. M. P.
Published: March 2023

Nickel-based superalloys, namely INCONEL® variants, have had an increase in applications throughout various industries like aeronautics, automotive and energy power plants. These superalloys can withstand high-temperature applications without suffering from creep, making them extremely appealing and suitable for manufactured goods such as jet engines or steam turbines. Nevertheless, INCONEL® alloys are considered difficult-to-cut materials, not only due to their superior material properties but also because of their poor thermal conductivity (k) and severe work hardening, which may lead to premature tool wear (TW) and poor final product finishing. In this regard, it is of paramount importance to optimise the machining parameters, to strengthen the process performance outcomes concerning the quality and cost of the product. The present review aims to systematically summarize and analyse the progress taken within the field of INCONEL® machining sensitively over the past five years, with some exceptions, and present the most recent solutions found in the industry, as well as the prospects from researchers. To accomplish this article, ScienceDirect, Springer, Taylor & Francis, Wiley and ASME have been used as sources of information as a result of great fidelity knowledge. Books from Woodhead Publishing Series, CRC Press and Academic Press have been also used. The main keywords used in searching information were: “Nickel-based superalloys”, “INCONEL® 718”, “INCONEL® 625” “INCONEL® Machining processes” and “Tool-wear mechanisms”. The combined use of these keywords was crucial to filter the huge information currently available about the evolution of INCONEL® machining technologies. As a main contribution to this work, three SWOT analyses are provided on information that is dispersed in several articles. It was found that significant progress in the traditional cutting tool technologies has been made, nonetheless, the machining of INCONEL® 718 and 625 is still considered a great challenge due to the intrinsic characteristics of those Ni-based-superalloys, whose machining promotes high-wear to the tools and coatings used.
A New Porous Nozzle for Aluminum Melts Purification—Preparation and Mathematical–Physical Model
Authors: Tan Yapeng , Zhang Guoqing , Lu Weihong , Yang Bo , Tang Zhichao , Xu Zhengbing , Zheng Qinjia , Zeng Jianmin , Tang Hongqun , Wang Junsheng , Jiang Aoke , Xiang Lei
Published: March 2023

Aluminum and its alloy castings are used more and more widely, and it is particularly important to remove impurities in the alloy. According to the principle of bubble floatation for degassing aluminum melt, a new porous nozzle with controllable pores was developed, and a hydraulic simulation experimental device was studied with the nozzle. The effects of the particle size ratio of the coarse sand to fine sand and volume fraction of fine sand on the porosity of the porous nozzle were studied by orthogonal experiment, and permeability and compressive strength of the porous nozzle were used as test indicators to determine the optimal parameters of preparation for the porous nozzle. The optimal parameters are fine sand of 100 mesh, and fine sand of 50 wt.%, binder of 17.5 wt.%, pore-forming agent of 6 wt.%, and pressure of making sample of 5 MPa. The nozzle with optimal parameters was prepared and tested, and the permeability is 112.2 × 10−12 m2 and the compressive strength is 2.3 MPa. In addition, a physical model of gas transmission in the porous nozzle was proposed. With the increase in the proportion of fine sand, the permeability of the porous nozzle decreases, the compressive strength increases, and the calculated porosity increases. The hydraulic simulation of melt injection was carried out, and the mathematical model for calculating the bubble diameter of bubble floatation was formulated. The model shows that the bubble diameter increases with the increase in gas flow rate. The experiment shows that the prepared porous nozzle has the merits of a simple preparation process and low-cost, which is expected to degas aluminum melts.
Fatigue Crack Growth Behavior and Failure Mechanism of Nickel-Based Alloy GH4169 under Biaxial Load Based on Fatigue Test of Cruciform Specimen
Authors: Wu Zhirong , Pan Ying , Lei Hang , Wang Shuaiqiang , Fang Lei
Published: March 2023

Due to the complex geometry and various cyclic loads, aeroengine components are often in a multiaxial complex stress state during service. Multiaxial fatigue is a major cause of many air accidents. It is of great significance to study the fatigue failure mechanism of aeronautical materials. This paper carries out biaxial fatigue tests on cruciform specimens and uses the surface replication method to record the initiation and propagation process of crack. Based on these fatigue tests, this paper studies the multiaxial fatigue characteristics of nickel-based alloy GH4169 for aeroengines and analyzes the fatigue crack growth behavior and failure mechanism of nickel-based alloys under a complex multiaxial stress state.
Al-Si10-Mg Manufactured by Selective Laser Melting: Microstructure Sensitivity to Close Values of the Heat Input
Authors: Leo Paola , Del Prete Antonio , Primo Teresa , Nacucchi Michele
Published: March 2023

Selective Laser Melting (SLM) is an attractive Additive Manufacturing (AM) technology for the fabrication of metallic components with complex structures and high performances. This process fulfills the goals of sustainable production by reducing material waste, optimizing product topology, and recycling metallic powder. Aluminum alloys exhibit also sustainable performances being lightweight and recyclable. Al-Si10-Mg alloy is suitable for SLM processing due to its good castability, good strength, wear, and corrosion resistance. However, the laser processing of aluminum alloys to date needs to be optimized. In this study, the authors have analyzed the role of close values of heat input on microstructure and defects (Electron and Optical microscope, DRX analysis), porosity (optical microscope and X-ray tomography), melting pool geometries (both in transversal and longitudinal sections of the samples) and mechanical performance (hardness and tensile test) of Al-Si10-Mg samples. The results have shown that even at very close values of energy density, the microstructure and properties of the samples differ from each other.
Impact of Isothermal Aging on Mechanical Properties of 92.8%Sn-3%Ag-0.5%Cu-3.3%Bi (Cyclomax) Solder Joints
Authors: Hamasha Mohammad M. , Hamasha Khozima , Hamasha Sa’d
Published: March 2023

During operation, electronic components are exposed to high temperatures that may last for long periods, depending on the operating duration. Solder joints are one of the components most affected by thermal aging while in service. In this research, the effect of thermal aging duration and temperature on the mechanical properties of 92.8%Sn-3%Ag-0.5%Cu-3.3%Bi (Cyclomax) was investigated. The novelty of this work lies in the study of the important properties of a new generation of Sn-Ag-Cu (SAC) materials (i.e., Cyclomax). Cyclomax is rare in industry and immature in research. To understand the effect of thermal aging, the microstructure was investigated, and changes in it and its mechanical properties were observed. To simulate solder joints in electronic devices, samples of solder balls were prepared and attached to copper pads on electronic boards. Most samples were then treated at 150 °C or 100 °C for up to 1000 h and some samples were left untreated for comparison. A scanning electron microscope (SEM) was used to obtain images of the microstructure. The shear stress–shear strain relationships, including the ultimate shear strength (USS), the modulus of elasticity and the ultimate energy (UE), were investigated. The microstructure images indicated the presence of a layer of Cu6Sn5 on top of the copper pad before thermal aging was applied. The thickness of this layer increased with the application of thermal aging over time. The results for the shear stress–shear strain relationship indicate that all of the USS, the total energy (TE) to shear off the solder balls and the UE decreased at the beginning of the thermal aging and then reversed to increase later. In general, isothermal aging reduces the performance of Cyclomax solder joints in terms of the minimum force and energy required to separate and subsequently damage electronic components.
Decoding Metabolic Reprogramming in Plants under Pathogen Attacks, a Comprehensive Review of Emerging Metabolomics Technologies to Maximize Their Applications
Authors: Serag Ahmed , Salem Mohamed A. , Gong Shilin , Wu Jian-Lin , Farag Mohamed A.
Published: March 2023

In their environment, plants interact with a multitude of living organisms and have to cope with a large variety of aggressions of biotic or abiotic origin. What has been known for several decades is that the extraordinary variety of chemical compounds the plants are capable of synthesizing may be estimated in the range of hundreds of thousands, but only a fraction has been fully characterized to be implicated in defense responses. Despite the vast importance of these metabolites for plants and also for human health, our knowledge about their biosynthetic pathways and functions is still fragmentary. Recent progress has been made particularly for the phenylpropanoids and oxylipids metabolism, which is more emphasized in this review. With an increasing interest in monitoring plant metabolic reprogramming, the development of advanced analysis methods should now follow. This review capitalizes on the advanced technologies used in metabolome mapping in planta, including different metabolomics approaches, imaging, flux analysis, and interpretation using bioinformatics tools. Advantages and limitations with regards to the application of each technique towards monitoring which metabolite class or type are highlighted, with special emphasis on the necessary future developments to better mirror such intricate metabolic interactions in planta.
Metabolomic Analysis Demonstrates the Impacts of Polyketide Synthases PKS14 and PKS15 on the Production of Beauvericins, Bassianolide, Enniatin A, and Ferricrocin in Entomopathogen Beauveria bassiana
Authors: Toopaang Wachiraporn , Panyawicha Kullyanee , Srisuksam Chettida , Hsu Wei-Chen , Lin Ching-Chih , Tanticharoen Morakot , Yang Yu-Liang , Amnuaykanjanasin Alongkorn
Published: March 2023

Beauveria bassiana is a globally distributed entomopathogenic fungus that produces various secondary metabolites to support its pathogenesis in insects. Two polyketide synthase genes, pks14 and pks15, are highly conserved in entomopathogenic fungi and are important for insect virulence. However, understanding of their mechanisms in insect pathogenicity is still limited. Here, we overexpressed these two genes in B. bassiana and compared the metabolite profiles of pks14 and pks15 overexpression strains to those of their respective knockout strains in culture and in vivo using tandem liquid chromatography-mass spectrometry (LC-MS/MS) with Global Natural Products Social Molecular Networking (GNPS). The pks14 and pks15 clusters exhibited crosstalk with biosynthetic clusters encoding insect-virulent metabolites, including beauvericins, bassianolide, enniatin A, and the intracellular siderophore ferricrocin under certain conditions. These secondary metabolites were upregulated in the pks14-overexpressing strain in culture and the pks15-overexpressing strain in vivo. These data suggest that pks14 and pks15, their proteins or their cluster components might be directly or indirectly associated with key pathways in insect pathogenesis of B. bassiana, particularly those related to secondary metabolism. Information about interactions between the polyketide clusters and other biosynthetic clusters improves scientific understanding about crosstalk among biosynthetic pathways and mechanisms of pathogenesis.
Electrically Inspired Flexible Electrochemical Film Power Supply for Long-Term Epidermal Sensors
Authors: Zheng Hao , Zhang Xingguo , Li Chengcheng , Zhu Wangwang , Li Dachao , Pu Zhihua
Published: March 2023

This paper, for the first time, reports an electrically inspired flexible electrochemical film power supply for long-term epidermal sensors. This device can periodically provide electrical power for several hours after a short-time electrical activation. The electrical activation makes acetylcholine, which is infused into the subcutaneous tissue by iontophoresis. The interstitial fluid (ISF) with glucose molecules is then permeated autonomously for several hours. At this period, the device can provide electrical power. The electrical power is generated from the catalyzing reaction between the glucose oxidase immobilized on the anode and the permeated glucose molecules. After the ISF permeation stops, we give a short-time electrical activation to provide electrical power for several hours again. The power supply is flexible, which makes it adaptively conform to skin. The episodic short-time electrical activation can be enabled by an integrated small film lithium-ion battery. This method extends the service life of a lithium-ion battery 10-fold and suggests the application of small lithium-ion batteries for long-term epidermal sensors.
How Do Diet Patterns, Single Foods, Prebiotics and Probiotics Impact Gut Microbiota?
Authors: Piccioni Andrea , Covino Marcello , Candelli Marcello , Ojetti Veronica , Capacci Annunziata , Gasbarrini Antonio , Franceschi Francesco , Merra Giuseppe
Published: March 2023

The human gastrointestinal tract hosts a complex and dynamic population of commensal bacterial species, which have coevolved with the host, generating a symbiotic relationship. Some compounds present in foods, such as polyols, prebiotic fibers, or phenolic compounds, are poorly metabolized and absorbed by the host before the transformation guided by the colonic microbiota. By influencing gut microbiota, diet plays a fundamental role in understanding the beneficial effects of the gut microbiota on the host, including its long-term metabolism. The idea that probiotics can act not only by influencing the colonizing microbiota opens the door to a wider range of probiotic possibilities, encouraging innovation in the field. Furthermore, it has been shown both that some probiotics increase phagocytosis or the activity of natural killer cells. Current prebiotics are mainly based on carbohydrates, but other substances, such as polyphenols and polyunsaturated fatty acids, could exert prebiotic effects. A prebiotic substance has been defined as ‘a substrate that is selectively used by host microorganisms that confer a health benefit’, and so can interact with the gut microbiota through competition for nutrients, antagonism, cross-feeding, and support for microbiota stability. Influencing its composition in terms of richness and diversity, food components have a key impact on the intestinal microbiota. Eating habits can strongly influence the composition of the intestinal microbiota. A healthy intestinal microbiota is essential for maintaining general health, and diet is one of the major modulators of this fascinating world of microorganisms. This must give us one more reason to adopt a healthy lifestyle.
Human Pathogens in Primary Production Systems
Authors: Overbeek Leo van
Published: March 2023

Human pathogenic micro-organisms can contaminate plants [...]
Potential of Indigenous Strains Isolated from the Wastewater Treatment Plant of a Crude Oil Refinery
Authors: Viggor Signe , Jõesaar Merike , Peterson Celeste , Teras Riho , Kivisaar Maia
Published: March 2023

Contamination of the environment with crude oil or other fuels is an enormous disaster for all organisms. The microbial communities for bioremediation have been an effective tool for eliminating pollution. This study aimed to determine individual cultures’ and a strain mixture’s ability to utilize alkanes (single alkanes and crude oil). The proper study of pure cultures is necessary to design synergistically working consortia. The Acinetobacter venetianus ICP1 and Pseudomonas oleovorans ICTN13 strains isolated from a wastewater treatment plant of a crude oil refinery can grow in media containing various aromatic and aliphatic hydrocarbons. The genome of the strain ICP1 contains four genes encoding alkane hydroxylases, whose transcription depended on the length of the alkane in the media. We observed that the hydrophobic cells of the strain ICP1 adhered to hydrophobic substrates, and their biofilm formation increased the bioavailability and biodegradation of the hydrocarbons. Although strain ICTN13 also has one alkane hydroxylase-encoding gene, the growth of the strain in a minimal medium containing alkanes was weak. Importantly, the growth of the mixture of strains in the crude oil-containing medium was enhanced compared with that of the single strains, probably due to the specialization in the degradation of different hydrocarbon classes and co-production of biosurfactants.
Rare Bacteria Can Be Used as Ecological Indicators of Grassland Degradation
Authors: Liu Mengjun , Ren Yue , Zhang Weihong
Published: March 2023

Grassland degradation is a major ecological problem at present, leading to changes in the grassland environment and the soil microbial community. Here, based on full-length 16S rRNA gene sequencing, we highlight the importance of small-scale environmental changes on the Qinghai-Tibet Plateau grassland for the composition and assembly processes of abundant and rare bacterial taxa. The results showed that grassland vegetation coverage affected the taxonomic and phylogenetic composition of rare bacterial taxa more than abundant bacterial taxa. The taxonomic composition and phylogenetic composition of rare bacterial taxa were also affected by soil nutrients. The relative contribution of deterministic processes (variable selection and homogeneous selection) to rare bacterial taxa was higher than that of the abundant bacterial taxa. The competitive potential within rare bacterial taxa was lower than that of the competitive potential between rare and non-rare bacterial taxa or within non-rare bacterial taxa. The assembly of rare bacterial taxa was more susceptible to environmental changes caused by grassland degradation than the abundant bacterial taxa. Furthermore, the distribution of rare bacterial taxa in the different degraded grassland soil was more local than that of abundant bacterial taxa. Thus, rare bacterial taxa could be considered an ecological indicator of grassland degradation. These findings help to improve our understanding of the composition and assembly mechanism of the bacterial communities in degraded grassland and provide a basis for the establishment of the grassland degradation management strategy.
Distribution of Se in Floating Coals with Densimetric Fractions in China
Authors: Zhang Guchun , Feng Qiyan , Zhao Heng , Zhang Na , Wu Meng , Wang Xiaoqing , Wen Mingzhong , Deng Yexin , Yang Zhao
Published: March 2023

Scholars at home and abroad have studied the concentrations of Se in coal and the relationship between Se and sulfur assignment. However, little attention has been paid to the study of Se in floating coal, especially the distribution pattern of Se in floating coal of densimetric fractions and the influencing factors. A total of 138 coal samples were collected from 14 provinces and cities in China to test the Se and sulfur concentrations in coal, and we carried out the comparison of Se with forms of sulfur with 81 of them. A total of 10 coal samples were selected for float-and-sink analyses to investigate the distribution pattern of Se in floating coal. The results showed that the average Se concentration of Chinese coal was 2.26 μg/g, which is identical with the results of previous research studies, which found an average Se concentration of 2~3 μg/g. Selenium was not uniformly distributed in floating coals of densimetric fractions but it had some regularity. The main controlling factor was the sulfur content in the coal. The Se concentrations of the high-sulfur coal showed a “linear growth” distribution with an increasing density, the Se concentrations of the floating coal in each densimetric fraction increased slowly and the Se concentrations of the floating coal of a densimetric fraction > 2.00 g/cm3 increased sharply. The other controlling factor was the ash yield of the coal. The Se concentrations of the low–medium-sulfur floating coal showed a “parabolic-like” distribution, i.e., low Se concentrations at both ends and high Se concentrations at the middle densimetric fraction. With the increase in the ash content of the coal from 18.23% to 51.92%, the densimetric fraction with the highest Se concentration gradually progressed from 1.40 g/cm3 to 1.50 g/cm3, 1.60 g/cm3 and 1.80 g/cm3 in order. The correlation between the selenium of the raw coal from different regions and the total sulfur, pyrite sulfur and organic sulfur was not significant. However, there existed a significant correlation between Se, total sulfur, pyrite sulfur and organic sulfur in floating coals from the same mining area and depositional environment, among which pyrite sulfur was the most correlated with Se, followed by total sulfur and organic sulfur.
Multi-Proxies Analysis of Organic Matter Accumulation of the Late Ordovician–Early Silurian Black Shale in the Lower Yangtze Region, South China
Authors: Zhang Chengcheng , Fang Chaogang , Zhao Qing , Meng Guixi , Zhou Daorong , Li Jianqing , Shao Wei
Published: March 2023

The evolutional process of palaeoceanic environment and its effect on the accumulation of organic matter during the Ordovician–Silurian transition in Lower Yangtze region has been overlooked compared to that in Upper Yangtze region of South China, although their paleogeographic settings were expected to be discrepant. This paper documents the marine depositional environment, paleoclimate, and sediment supply changes, and discusses their roles in controlling the organic matter enrichment in sedimentary rocks within the Ordovician–Silurian transition of the Lower Yangtze region, using the latest geochemical data of the continuous drilling core. The stratigraphic framework of the Ordovician–Silurian transition in the Lower Yangtze region is composed of two third-order sequences, each of which can be subdivided into a lower TST (transgressive systems tract) and an upper RST (regressive systems tract). TST1 represented an evident depositional transition stage which was marked by the ending of the underlying carbonate sediments and the initiation of the terrigenous clastic-dominated sediments. Geochemical proxies indicate that the relatively low productivity, dysoxic water column condition, and high sediment supply flux collectively resulted in inadequate organic matter hosted in deposits of the TST1. During the depositional period of RST1, the global sea level declined due to the Hirnantian glaciation age. The icehouse also caused the decrease in overall river flux and, thus, the terrigenous clastic sediment supply. The icehouse also strengthened the upwelling that occurred in the Lower Yangtze sea. The upwelling boosted the marine algae explosion through the delivery of abundant nutrients, which not only enhanced paleoproductivity but also led to an anoxic environment by oxygen consumption. Such high paleoproductivity, anoxic water column environment, and low sediment supply flux caused the deposition of organic-rich shale. The sea level rose during the TST2 due to the ending of an ice age. The relatively large water depth and high paleoproductivity associated with volcanic eruptions are the main factors that caused the enrichment of organic matter during this stage. During the deposition of RTS2, the increase of sediment supply flux resulted in a decrease in accommodation space and water depth and the dilution of organic matter in deposits, which was the primary constraint of organic matter accumulation.
Leaching Mechanism of Aluminum during Column Leaching of Ion-Adsorption Rare Earth Ore Using Magnesium Sulfate
Authors: Guo Qi , Li Zheng , Pan Jiaxin , Li Bo , Zhao Longsheng , Liu Depeng , Zheng Xudong , Wang Chunmei
Published: March 2023

Aluminum is a significant impurity in the ion-adsorption rare earth ore. The changes in the occurrences of aluminum have a great influence on the leaching of the rare earth ore. In this paper, the column leaching method was employed using magnesium sulfate as a leaching agent to investigate the effects of pH and magnesium sulfate concentration in the leaching agent on the leaching of aluminum and rare earths. The results show that at low magnesium sulfate concentrations, the leaching of rare earths is greatly enhanced, while the leaching of aluminum is not significantly affected by a decrease in the pH of leaching agent. At high magnesium sulfate concentrations, a slight increase in the leaching of rare earths is observed, accompanied by a significant increase in the leaching of aluminum upon decreasing the pH of the leaching agent. The leaching behavior of aluminum is related to the changes in the occurrences of aluminum during the leaching process. At low magnesium sulfate concentrations, low pH promotes the transition of Hy-Al to Sol-Al, but due to the low Mg2+ concentration in the leaching agent, Sol-Al is back-adsorbed onto the clays and transformed into Ex-Al, resulting in no significant increase in the aluminum content in the leach solution. However, at higher magnesium sulfate concentrations, aluminum in the leach solution comes mainly from the transformation of Ex-Al. Lowering the pH of the leaching agent can significantly promote the transition of Hy-Al to Sol-Al, thereby greatly increasing the aluminum content in the leach solution. The above results provide theoretical support for the optimization of the in situ leaching of ion-adsorption rare earth ore using magnesium sulfate.
Incorporating Environmental Impacts into Short-Term Mine Planning: A Literature Survey
Authors: Rahnema Milad , Amirmoeini Bahar , Moradi Afrapoli Ali
Published: March 2023

This paper aims to address the significant financial, environmental, and social risks posed by climate change to the mining industry, which is responsible for approximately 8% of global greenhouse gas emissions. With 70% of mining projects for the six largest mining companies located in water-stressed regions, the industry is facing increasing pressure to reduce its impact. Our study investigates the applicability of multi-objective optimization to integrate environmental impact considerations into short-term planning for mining operations. To achieve this, we have reviewed similar studies in various industries and developed an integrated planning framework that incorporates environmental considerations into production planning for surface mines. Our framework has the potential to be utilized in both short- and long-term planning horizons, promoting sustainable mining practices. Through this research, we aim to provide mining engineers with a more comprehensive and effective approach to minimize the environmental impacts of their operations while maintaining efficient production.
Physicochemical Characterization and Antitumor Activity of Fucoidan and Its Degraded Products from Sargassum hemiphyllum (Turner) C. Agardh
Authors: Luo Baozhen , Wang Zhuo , Chen Jianping , Chen Xuehua , Li Jiarui , Li Yinghua , Li Rui , Liu Xiaofei , Song Bingbing , Cheong Kit-Leong , Zhong Saiyi
Published: March 2023

Fucoidan has many biological functions, including anti-tumor activity. Additionally, it has been suggested that low-molecular-weight fucoidans have greater bioactivities. This study aimed to examine the degradation, purification, physicochemical characterization and in vitro antitumor activity of fucoidan from Sargassum hemiphyllum (Turner) C. Agardh. Fucoidan was isolated using DEAE-cellulose-52 (F1, F2), Vc-H2O2 degration, and Sepharose CL-6B gel (DF1, DF2) from crude Sargassum fucoidans. Physicochemical characteristics of four isolated fucoidans were examined using chemical and monosaccharide composition, average molecular weight (Mw), and FTIR. Furthermore, the anti-proliferative effects of purified fucoidans on human hepatocellular carcinoma cells (HepG2), human Burkitt Lymphoma cells (MCF-7), human uterine carcinoma cells (Hela) and human lung cancer cells (A549) were analyzed by MTT method. The apoptosis of HepG2 cells was detected by flow cytometry. Our data suggest that the contents of polysaccharide, L-fucose and sulfate of DF2 were the highest, which were 73.93%, 23.02% and 29.88%, respectively. DF1 has the smallest molecular weight (14,893 Da) followed by DF2 (21,292 Da). The four fractions are mainly composed of fucose, mannose and rhamnose, and the infrared spectra are similar, all of which contain polysaccharide and sulfate characteristic absorption peaks. The results of MTT assay showed that the four fractions had inhibitory effects on HepG2 and A549 in the range of 0.5–8 mg/mL, and the four fractions had strong cytotoxic effects on HepG2 cells. DF2 had the best inhibitory effect on HepG2 (IC50 = 2.2 mg/mL). In general, the antitumor activity of Sargassum fucoidans is related to the content of L-fucose, sulfate and molecular weight, and Sargassum fucoidan has the best inhibitory effect on HepG2 hepatocellular carcinoma cells. Furthermore, when compared to MCF-7, Hela, and A549 cells, Sargassum fucoidans had the best capacity to reduce the viability of human hepatocellular carcinoma cells (HepG2) and to induce cell apoptosis, proving itself to have a good potential in anti-liver cancer therapy.
Enhanced Remdesivir Analogues to Target SARS-CoV-2
Authors: Majima Ryuichi , Edwards Tiffany C. , Dreis Christine D. , Geraghty Robert J. , Bonnac Laurent F.
Published: March 2023

We report the short synthesis of novel C-nucleoside Remdesivir analogues, their cytotoxicity and an in vitro evaluation against SARS-CoV-2 (CoV2). The described compounds are nucleoside analogues bearing a nitrogen heterocycle as purine analogues. The hybrid structures described herein are designed to enhance the anti-CoV2 activity of Remdesivir. The compounds were evaluated for their cytotoxicity and their anti-CoV2 effect. We discuss the impact of combining both sugar and base modifications on the biological activities of these compounds, their lack of cytotoxicity and their antiviral efficacy.
Identification of Potential Inhibitors for the Treatment of Alkaptonuria Using an Integrated In Silico Computational Strategy
Authors: Zaib Sumera , Rana Nehal , Hussain Nadia , Ogaly Hanan A. , Dera Ayed A. , Khan Imtiaz
Published: March 2023

Alkaptonuria (AKU) is a rare genetic autosomal recessive disorder characterized by elevated serum levels of homogentisic acid (HGA). In this disease, tyrosine metabolism is interrupted because of the alterations in homogentisate dioxygenase (HGD) gene. The patient suffers from ochronosis, fractures, and tendon ruptures. To date, no medicine has been approved for the treatment of AKU. However, physiotherapy and strong painkillers are administered to help mitigate the condition. Recently, nitisinone, an FDA-approved drug for type 1 tyrosinemia, has been given to AKU patients in some countries and has shown encouraging results in reducing the disease progression. However, this drug is not the targeted treatment for AKU, and causes keratopathy. Therefore, the foremost aim of this study is the identification of potent and druggable inhibitors of AKU with no or minimal side effects by targeting 4-hydroxyphenylpyruvate dioxygenase. To achieve our goal, we have performed computational modelling using BioSolveIT suit. The library of ligands for molecular docking was acquired by fragment replacement of reference molecules by ReCore. Subsequently, the hits were screened on the basis of estimated affinities, and their pharmacokinetic properties were evaluated using SwissADME. Afterward, the interactions between target and ligands were investigated using Discovery Studio. Ultimately, compounds c and f were identified as potent inhibitors of 4-hydroxyphenylpyruvate dioxygenase.
Influence of β-Cyclodextrin Methylation on Host-Guest Complex Stability: A Theoretical Study of Intra- and Intermolecular Interactions as Well as Host Dimer Formation
Authors: Geue Niklas , Alcázar Jackson J. , Campodónico Paola R.
Published: March 2023

Understanding the non-covalent interactions in host-guest complexes is crucial to their stability, design and applications. Here, we use density functional theory to compare the ability of β-cyclodextrin (β-CD) and heptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD) to encapsulate the model guest phenol. For both macrocycles, we quantify the intramolecular interactions before and after the formation of the complex, as well as the intermolecular host-guest and host-host dimer interactions. These are individually classified as van der Waals interactions or hydrogen bonds, respectively. The results show a stronger intramolecular binding energy of β-CD, with the absolute difference being −5.53 kcal/mol relative to DM-β-CD. Consequently, the intermolecular interactions of both cyclodextrins with phenol are affected, such that the free binding energy calculated for the DM-β-CD/phenol complex (−5.23 kcal/mol) is ≈50% more negative than for the complex with β-CD (−2.62 kcal/mol). The latter is in excellent agreement with the experimental data (−2.69 kcal/mol), which validates the level of theory (B97-3c) used. Taken together, the methylation of β-CD increases the stability of the host-guest complex with the here studied guest phenol through stronger van der Waals interactions and hydrogen bonds. We attribute this to the disruption of the hydrogen bond network in the primary face of β-CD upon methylation, which influences the flexibility of the host toward the guest as well as the strength of the intermolecular interactions. Our work provides fundamental insights into the impact of different non-covalent interactions on host-guest stability, and we suggest that this theoretical framework can be adapted to other host-guest complexes to evaluate and quantify their non-covalent interactions.
Tackling Issues Observed during the Development of a Liquid Chromatography Method for Small Molecule Quantification in Antibody-Chelator Conjugate
Authors: Bouvarel Thomas , Bremeyer Nadine , Gao Mimi , Holkenjans Wiebke , Hetzel Terence , Pell Reinhard , D’Atri Valentina , Guillarme Davy
Published: March 2023

In the context of targeted radionuclide therapy, antibody-chelator conjugates (ACCs) are an evolving class of antibody-related drugs with promising applications as tumor-targeted pharmaceuticals. Generally, a typical ACC consists of a recombinant monoclonal antibody (mAb) coupled to radionuclide via a chelating agent. Characterizing the ACC structure represents an analytical challenge since various impurities must be constantly monitored in the presence of formulation components during the quality control (QC) process. In this contribution, a reliable method devoted to the monitoring of an ACC sample, and its small molecule-related synthesis impurities, has been developed via liquid chromatography (LC). A problem-solving approach of common analytical issues was used to highlight some major issues encountered during method development. This included separation of poorly retained impurities (issue #1); interferences from the formulation components (issue #2); analysis of impurities in presence of ACC at high concentration (issue #3); and recovery of impurities during the whole analytical procedure (issue #4). To the best of our knowledge, this is the first time that a chromatographic method for the analysis of ACC synthesis impurities is presented. In addition, the developed approach has the potential to be more widely applied to the characterization of similar ACCs and other antibody-related drugs.
Photocatalytic Applications of ReS2-Based Heterostructures
Authors: Wang Nan , Li Yashu , Wang Lin , Yu Xuelian
Published: March 2023

ReS2-based heterostructures, which involve the coupling of a narrow band-gap semiconductor ReS2 with other wide band-gap semiconductors, have shown promising performance in energy conversion and environmental pollution protection in recent years. This review focuses on the preparation methods, encompassing hydrothermal, chemical vapor deposition, and exfoliation techniques, as well as achievements in correlated applications of ReS2-based heterostructures, including type-I, type-II heterostructures, and Z-scheme heterostructures for hydrogen evolution, reduction of CO2, and degradation of pollutants. We believe that this review provides an overview of the most recent advances to guide further research and development of ReS2-based heterostructures for photocatalysis.
A Facile Microwave Hydrothermal Synthesis of ZnFe2O4/rGO Nanocomposites for Supercapacitor Electrodes
Authors: Mo Xiaoyao , Xu Guangxu , Kang Xiaochan , Yin Hang , Cui Xiaochen , Zhao Yuling , Zhang Jianmin , Tang Jie , Wang Fengyun
Published: March 2023

As a typical binary transition metal oxide, ZnFe2O4 has attracted considerable attention for supercapacitor electrodes due to its high theoretical specific capacitance. However, the reported synthesis processes of ZnFe2O4 are complicated and ZnFe2O4 nanoparticles are easily agglomerated, leading to poor cycle life and unfavorable capacity. Herein, a facile microwave hydrothermal process was used to prepare ZnFe2O4/reduced graphene oxide (rGO) nanocomposites in this work. The influence of rGO content on the morphology, structure, and electrochemical performance of ZnFe2O4/rGO nanocomposites was systematically investigated. Due to the uniform distribution of ZnFe2O4 nanoparticles on the rGO surface and the high specific surface area and rich pore structures, the as-prepared ZnFe2O4/rGO electrode with 44.3 wt.% rGO content exhibits a high specific capacitance of 628 F g−1 and long cycle life of 89% retention over 2500 cycles at 1 A g−1. This work provides a new process for synthesizing binary transition metal oxide and developing a new strategy for realizing high-performance composites for supercapacitor electrodes.