bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Modeling of Shockwaves Driven by High-Energy Particle Beam Radiation in Tungsten-Made Structures
Authors: Scapin Martina , Peroni Lorenzo
Published: April 2022

The investigation of wave propagation in solids requires the development of reliable methods for the prediction of such dynamic events in which the involved materials cover wide ranges of different possible states, governed by plasticity, equation of state, and failure. In the present study, the wave propagation in metals generated by the interaction of high-energy proton beams with solids was considered. In this condition, axisymmetric waves were generated, and, depending on the amount of the delivered energy, different regimes (elastic, plastic, or shock) can be reached. Nonlinear numerical analyses were performed to investigate the material response. The starting point was the energy map delivered into the component as the consequence of the beam impact. The evolution of both hydrodynamic and mechanical quantities was followed starting from the impact and the effects induced on the hit component were investigated. The results showed the portion of the component close to the beam experiences pressure and temperature increase during the deposition phase. The remaining part of the component is traversed by the generated shockwave, which induces high values of strain in a short time or even the failure of the component.
A Review of the Friction Stir Welding of Dissimilar Materials between Aluminum Alloys and Copper
Authors: Sun Yumeng , Gong Wenbiao , Feng Jiacheng , Lu Guipeng , Zhu Rui , Li Yupeng
Published: April 2022

With the rapid development of various industries, the connection of copper and aluminum is in high demand. However, as a solid-phase connection technology, friction stir welding has a potential application prospect in the connection of copper and aluminum. This paper comprehensively summarizes the most recent 20 years of the literature related to the friction stir welding of copper and aluminum. The application significance of copper and aluminum connectors is introduced, and the research field of the friction stir welding of copper and aluminum is analyzed and explored from the aspects of welding technology, microstructure and mechanical properties, as well as innovations and improvements in the welding process. In view of the research status of this field, the authors put forward their views and prospects for its future, aiming to provide a basis for researchers in this field.
Recovery of Graphite and Cathode Active Materials from Spent Lithium-Ion Batteries by Applying Two Pretreatment Methods and Flotation Combined with a Rapid Analysis Technique
Authors: Qiu Hao , Peschel Christoph , Winter Martin , Nowak Sascha , Köthe Johanna , Goldmann Daniel
Published: April 2022

This work investigates the comprehensive recycling of graphite and cathode active materials (LiNi0.6Mn0.2Co0.2O2, abbreviated as NMC) from spent lithium-ion batteries via pretreatment and flotation. Specific analytical methods (SPME-GC-MS and Py-GC-MS) were utilized to identify and trace the relevant influencing factors. Two different pretreatment methods, which are Fenton oxidation and roasting, were investigated with respect to their influence on the flotation effectiveness. As a result, for NMC cathode active materials, a recovery of 90% and a maximum grade of 83% were obtained by the optimized roasting and flotation. Meanwhile, a graphite grade of 77% in the froth product was achieved, with a graphite recovery of 75%. By using SPME-GC-MS and Py-GC-MS analyses, it could be shown that, in an optimized process, an effective destruction/removal of the electrolyte and binder residues can be reached. The applied analytical tools could be integrated into the workflow, which enabled process control in terms of the pretreatment sufficiency and achievable separation in the subsequent flotation.
Effect of Sealing Treatments on Erosion–Corrosion of a Fe-Based Amorphous Metallic Coating in 3.5 wt.% NaCl Solution with 2 wt.% Sand
Authors: Liu Mingming , Wang Zhengbin , Hu Hongxiang , Zhang Lianmin , Zheng Yugui
Published: April 2022

In this study, a Fe-based amorphous metallic coating (AMC) was sealed with three sealants, i.e., stearic acid, aluminum phosphate and cerium salt, respectively. Two types of electrochemical tests, namely the ex situ electrochemical impedance spectroscopy test and the in situ potentiostatic polarization test, were conducted to evaluate the erosion–corrosion resistance of as-sprayed and as-sealed AMCs. The results show that the aluminum phosphate–sealed AMC exhibits the best erosion–corrosion resistance with the higher critical flow velocity compared with the as-sprayed AMC, which is attributed to the deep penetration of aluminum phosphate and high hardness of the sealed layer. In contrast, the sealants of stearic acid and cerium salt are easily removed by sand particle impacting, deteriorating their erosion–corrosion resistance.
Compressive Property and Energy Absorption Capacity of Mg-Ceramic-Ni Foamsat Various Temperatures
Authors: Shi Shouquan , Sun Weibo , Zhang Xiaoru , Zhu Xianyong , Liu Jiaan
Published: April 2022

Mg–Ceramic–Ni hybrid foams were fabricated via continuousdepositing micro-arc oxidation (MAO) ceramic coating and electroless Ni coating on the surface of the AZ91D foam struts. Mechanical tests from room temperature (RT) to 300 °C were carried out to evaluate the compressive properties and energy absorption capacities of two types of foams, i.e., AZ91D alloy foams and corresponding hybrid foams. The effect of composite coatings and test temperature on the compressive property of the foams was studied. The experimental results show that the MAOand Ni coatings enhance the Mg foam struts, resulting in high compressive strength and energy absorption capacity at each testing temperature. In addition, the compressive properties are also depending on testing temperature. The different mechanical responses of the composite foams under various temperature conditions are mainly attributed to the different deformation behaviors and failure modes of the foam struts, which are confirmed by scanning electron microscopy (SEM) observation.
Investigations on Effects of Forming Parameters on Product Dimensions in Cold Drawing of AISI-316 Stainless Steel Rods
Authors: Hwang Yeong-Maw , Tsui Hiu Shan Rachel , Lin Man-Ru
Published: April 2022

Cold drawing is a commonly used metal forming technique carried out by pulling a billet through a die cavity to obtain desired dimensions. Ideally, the cross-sectional area of the drawn product should be equal to that of the die at its exit; however, the former one is always larger after drawing, in practice. In this study, cold drawing of an AISI-316 stainless steel rod is investigated through finite element analysis. The difference between the product radius and the die radius is denoted by ∆R. A series of simulations using combinations of various forming parameters, including semi-die angle, bearing ratio, reduction ratio, drawing speed and friction coefficient, are conducted to find out the dominant factors of ∆R. It is found that ∆R is mainly affected by semi-die angle, reduction ratio and friction. An empirical formula for ∆R, including various parameters, is established according to the simulation results and verified by drawing experiments as well. Using this empirical formula, the product dimensions can be predicted in advance and proper forming parameters can be chosen to decrease ∆R and improve the product quality.
Predictive Modeling of Thermally Assisted Machining and Simulation Based on RSM after WAAM
Authors: Tian Hongyu , Lu Zhenyang , Chen Shujun
Published: April 2022

The WAAM (Wire Arc Additive Manufacturing) process is well-respected because of its low cost and high deposition efficiency; nevertheless, the process has the limitations of high heat input and low forming accuracy. Hybrid manufacturing processes employing both additive and subtractive processes can effectively reduce shape error. The predictive modeling of surface roughness in thermally assisted machining is described in this paper on the basis of three important parameters: feed per tooth, spindle speed, and workpiece temperature. The predictive model indicates that temperature has a very significant influence on the surface quality. An experimental study on thermally assisted machining was performed to obtain the variation law of cutting surface quality with temperature in order to determine the optimal process interval of subtractive processes. Through finite element simulation of thermally assisted machining, the influence law of external main cutting force and the internal mean stress of the cutting material were determined.
Cluster Hardening Effects on Twinning in Mg-Zn-Ca Alloys
Authors: Liu Ruixue , Wang Jie , Wang Leyun , Zeng Xiaoqin , Jin Zhaohui
Published: April 2022

Twinning is a critical deformation mode in Mg alloys. Understanding deformation twinning (DT) is essential to improving mechanical properties of Mg alloys. To address the experimentally observed conspicuous hardening effects in Mg-1.8Zn-0.2Ca alloys, interactions between the {10–12} twin boundaries (TBs) and solute clusters in Mg-Zn-Ca alloys were examined via molecular dynamics (MD) simulations. We find that the Zn/Ca-containing clusters show different hindering effects on TBs and an increment in the applied shear stress of 100 MPa is required to accomplish the interaction between the boundary and the cluster with Ca content > 50 at%. The cluster hardening effects on twinning are positively correlated to the Ca content and the size of the clusters in Mg-Zn-Ca alloys.
Exploring Thermal Sensitivities and Adaptations of Oxidative Phosphorylation Pathways
Authors: Lemieux Hélène , Blier Pierre U.
Published: April 2022

Temperature shifts are a major challenge to animals; they drive adaptations in organisms and species, and affect all physiological functions in ectothermic organisms. Understanding the origin and mechanisms of these adaptations is critical for determining whether ectothermic organisms will be able to survive when faced with global climate change. Mitochondrial oxidative phosphorylation is thought to be an important metabolic player in this regard, since the capacity of the mitochondria to produce energy greatly varies according to temperature. However, organism survival and fitness depend not only on how much energy is produced, but, more precisely, on how oxidative phosphorylation is affected and which step of the process dictates thermal sensitivity. These questions need to be addressed from a new perspective involving a complex view of mitochondrial oxidative phosphorylation and its related pathways. In this review, we examine the effect of temperature on the commonly measured pathways, but mainly focus on the potential impact of lesser-studied pathways and related steps, including the electron-transferring flavoprotein pathway, glycerophosphate dehydrogenase, dihydroorotate dehydrogenase, choline dehydrogenase, proline dehydrogenase, and sulfide:quinone oxidoreductase. Our objective is to reveal new avenues of research that can address the impact of temperature on oxidative phosphorylation in all its complexity to better portray the limitations and the potential adaptations of aerobic metabolism.
iNovo479: Metabolic Modeling Provides a Roadmap to Optimize Bioproduct Yield from Deconstructed Lignin Aromatics by Novosphingobium aromaticivorans
Authors: Linz Alexandra M. , Ma Yanjun , Scholz Samuel , Noguera Daniel R. , Donohue Timothy J.
Published: April 2022

Lignin is an abundant renewable source of aromatics and precursors for the production of other organic chemicals. However, lignin is a heterogeneous polymer, so the mixture of aromatics released during its depolymerization can make its conversion to chemicals challenging. Microbes are a potential solution to this challenge, as some can catabolize multiple aromatic substrates into one product. Novosphingobium aromaticivorans has this ability, and its use as a bacterial chassis for lignin valorization could be improved by the ability to predict product yields based on thermodynamic and metabolic inputs. In this work, we built a genome-scale metabolic model of N. aromaticivorans, iNovo479, to guide the engineering of strains for aromatic conversion into products. iNovo479 predicted product yields from single or multiple aromatics, and the impact of combinations of aromatic and non-aromatic substrates on product yields. We show that enzyme reactions from other organisms can be added to iNovo479 to predict the feasibility and profitability of producing additional products by engineered strains. Thus, we conclude that iNovo479 can help guide the design of bacteria to convert lignin aromatics into valuable chemicals.
Design of 4.7 μm High-Efficiency Hybrid Dielectric Reflection Gratings
Authors: Wang Ye , Fu Xiuhua , Chen Yongyi , Lei Yuxin , Qin Li , Wang Lijun
Published: April 2022

Traditional reflective diffraction gratings working at 4.7 μm are fabricated by metal coatings. Due to the absorption of the metal itself, the diffraction efficiency (DE) could not reach over 95%. In this paper, we propose a 3 μm period multilayer grating design using hybrid multilayer dielectrics. With a layer of 0.353 μm Si and a layer of 0.905 μm SiO2 forming the rectangular grating, the maximum of larger than 99.99% and the overall first-order DE reached 97.88%. The usable spectrum width is larger than 0.2 μm, more than four times larger than that of the pure Si rectangular grating. This high DE multilayer grating is an ideal element for high-power laser systems with the spectrum beam combining method.
Enterococcus casseliflavus KB1733 Isolated from a Traditional Japanese Pickle Induces Interferon-Lambda Production in Human Intestinal Epithelial Cells
Authors: Satomi Shohei , Kokubu Daichi , Inoue Takuro , Sugiyama Masaya , Mizokami Masashi , Suzuki Shigenori , Murata Kazumoto
Published: April 2022

The association between lactic acid bacteria (LAB) and their immunostimulatory effects has attracted considerable attention; however, it remains unclear whether LAB can induce interferon-lambdas (IFN-λs) in human epithelial cells under conditions that do not mimic infection. In this study, we first employed a reporter assay to screen for a potential strain capable of inducing IFN-λ3 among 135 LAB strains derived from traditional Japanese pickles. Next, we assessed the strain’s ability to induce the expression of IFN-λ genes and interferon-stimulated genes (ISGs), and to produce IFN-λs. As a result, we screened and isolated Enterococcus casseliflavus KB1733 (KB1733) as a potential strain capable of inducing IFN-λ3 expression. Furthermore, we clarified that KB1733 induced the expression of IFN-λ genes and ISGs related to antiviral functions, and that KB1733 induced IFN-λ1 and -λ3 expression in a dose-dependent manner up to 10 μg/mL. In addition, KB1733 significantly increased IFN-λ1 production compared to Enterococcus casseliflavus JCM8723T, which belongs to the same genera and species as KB1733. In conclusion, we isolated a unique LAB strain from traditional Japanese pickles that is capable of stimulating IFN-λ production, although further study is needed to investigate how KB1733 protects against viruses in mice and humans.
Classification of Environmental Strains from Order to Genus Levels Using Lipid and Protein MALDI-ToF Fingerprintings and Chemotaxonomic Network Analysis
Authors: Levasseur Marceau , Hebra Téo , Elie Nicolas , Guérineau Vincent , Touboul David , Eparvier Véronique
Published: April 2022

During the last two decades, MALDI-ToF mass spectrometry has become an efficient and widely-used tool for identifying clinical isolates. However, its use for classification and identification of environmental microorganisms remains limited by the lack of reference spectra in current databases. In addition, the interpretation of the classical dendrogram-based data representation is more difficult when the quantity of taxa or chemotaxa is larger, which implies problems of reproducibility between users. Here, we propose a workflow including a concurrent standardized protein and lipid extraction protocol as well as an analysis methodology using the reliable spectra comparison algorithm available in MetGem software. We first validated our method by comparing protein fingerprints of highly pathogenic bacteria from the Robert Koch Institute (RKI) open database and then implemented protein fingerprints of environmental isolates from French Guiana. We then applied our workflow for the classification of a set of protein and lipid fingerprints from environmental microorganisms and compared our results to classical genetic identifications using 16S and ITS region sequencing for bacteria and fungi, respectively. We demonstrated that our protocol allowed general classification at the order and genus level for bacteria whereas only the Botryosphaeriales order can be finely classified for fungi.
Blast Furnace Slag, Post-Industrial Waste or Valuable Building Materials with Remediation Potential?
Authors: Dzięcioł Justyna , Radziemska Maja
Published: April 2022

In recent years, the construction industry has struggled with a variety of issues such as material availability, supply channel management, and the increasing cost of construction materials. These issues have encouraged the search for replacements and substitutes for existing construction materials. Blast Furnace Slag is used in the construction industry as a mineral amendment or aggregate. Their use in Earth Construction, due to their post-industrial origin, may be associated with increased levels of potentially toxic elements (PTE) in the soil. This study aimed to evaluate the effectiveness of the immobilization potential of Blast Furnace Slag and to compare it with the addition of Blast Furnace Slag with Activated Carbon using different concentrations of these amendments. We were able to determine the concentrations of selected PTE (zinc, copper, nickel, cadmium and lead) in the soil, roots and aerial parts of Lolium perenne L., using different concentrations of Blast Furnace Slag (3%, 5% and 10%), and Blast Furnace Slag with Activated Carbon (3% and 5%) as soil amendments. Measurements were carried out with Flame Atomic Absorption Spectrometry (FAAS). Both the addition of Blast Furnace Slag and Activated Carbon with Slag increased plant biomass. The addition of slag effectively reduced the zinc, copper, cadmium and lead content of the soil, while the addition of Activated Carbon slag significantly increased the content of selected PETs in the roots and aerial parts of plants. It was considered reasonable to use Blast Furnace Slag with the addition of Activated Carbon in supporting the processes of the assisted phytostabilization of PTE polluted soils.
Mechanical Behaviour of Anchored Rock Containing Weak Interlayer under Uniaxial Compression: Laboratory Test and Coupled DEM–FEM Simulation
Authors: Luo Xinyang , Cao Ping , Liu Taoying , Zhao Qingxiong , Meng Gang , Fan Zhi , Xie Weiping
Published: April 2022

The reason for instability in a rock mass with a weak interlayer is not only the sliding failure of the rock interlayer structural plane but also the tip crack propagation caused by the stress concentration at the tip of the interlayer. In this study, a uniaxial compression test of an anchored rock mass with a weak interlayer was carried out to determine the influence of the anchorage on the failure pattern and the strength of samples with different interlayer dip angles. In addition, the coupled DEM–FEM numerical simulation method was used to study the internal stress evolution of the sample and the stress distribution of the anchor under the anchorage effect. The results showed that the anchorage effect on reinforcement and strength enhancement was greatest for the sample with an interlayer dip angle of 30°. Under the anchorage effect, crack initiation was limited and there was more shear failure in the samples. The reinforcement range of the anchorage effect for anchors with restrained ends was larger than for anchors with free ends. When the rock–anchor interface was unbonded, the effect of the free-ends anchor reflected the residual friction, but the restrained-ends anchor still worked by limiting the lateral expansion of the rocks. The stress values and deformation of the anchors decreased gradually with an increase in dip angle.
Novel Technology for Comprehensive Utilization of Low-Grade Iron Ore
Authors: Zhu Xinran , Qin Yonghong , Han Yuexin , Li Yanjun
Published: April 2022

In this study, a novel technology for the comprehensive utilization of low-grade iron ore is presented. For the iron ore with a Fe content of 24.91%, a pilot-scale study of pre-concentration, suspension magnetization roasting, grinding, and low-intensity magnetic separation was conducted, and an iron concentrate with a grade of 62.21% and a recovery of 85.72% was obtained. The products were analysed using chemical elemental analysis, particle size analysis, X-ray diffraction, scanning electron microscopy, and vibrating sample magnetometry. The results indicated that hematite was reduced by CO and H2 mixture and transformed into ferrimagnetic magnetite in the suspension magnetization roasting, which was easily recovered in the subsequent magnetic separation. Additionally, a pre-concentration tailing with a SiO2 content of 81.55% and a magnetic tailing of the roasted ore with a SiO2 content of 79.57% were obtained, which can be used as building materials. This presents significant implications for the comprehensive utilization of low-grade iron ore.
Synthesis of Functionalized Six-Membered-Ring Azahelicenes
Authors: Fontana Francesca , Bertolotti Benedetta
Published: April 2022

Functionalization, namely the introduction of side groups onto the molecular scaffold of a helicene, may have either the purpose of modifying the electronic properties of the parent helicene, e.g., by adding electron-withdrawing or electron-donating groups, or the scope of providing the helicene with a “handle”, which can be reacted to bind the molecule to another molecule or to a solid structure, such as a carbon or metal surface, or again to allow for complexation of the helicene with metal ions. The possible approaches are two-fold: the synthesis of the helicene can be performed using starting materials that already contain a side group, or the side group can be introduced after the synthesis of the parent helicene. As azahelicenes are helicenes bearing one or more nitrogen atom(s) in the molecular framework, parent azahelicenes can be functionalized on carbon atoms by exploiting the presence of the electron-withdrawing nitrogen atom. Moreover, they can be transformed into quaternary salts, whose properties are quite different from those of the parent azahelicenes in terms of the solubility and electronic properties. This review aims to provide a survey of the different synthetic methods available to attain this fascinating class of compounds.
Advances in the Development of SARS-CoV-2 Mpro Inhibitors
Authors: Agost-Beltrán Laura , de la Hoz-Rodríguez Sergio , Bou-Iserte Lledó , Rodríguez Santiago , Fernández-de-la-Pradilla Adrián , González Florenci V.
Published: April 2022

Since the outbreak of COVID-19, one of the strategies used to search for new drugs has been to find inhibitors of the main protease (Mpro) of the virus SARS-CoV-2. Initially, previously reported inhibitors of related proteases such as the main proteases of SARS-CoV and MERS-CoV were tested. A huge effort was then carried out by the scientific community to design, synthesize and test new small molecules acting as inactivators of SARS-CoV-2 Mpro. From the chemical structure view, these compounds can be classified into two main groups: one corresponds to modified peptides displaying an adequate sequence for high affinity and a reactive warhead; and the second is a diverse group including chemical compounds that do not have a peptide framework. Although a drug including a SARS-CoV-2 main protease inhibitor has already been commercialized, denoting the importance of this field, more compounds have been demonstrated to be promising potent inhibitors as potential antiviral drugs.
The Isolation and Characterization of Antagonist Trichoderma spp. from the Soil of Abha, Saudi Arabia
Authors: Alwadai Aisha Saleh , Perveen Kahkashan , Alwahaibi Mona
Published: April 2022

Background: The genus Trichoderma is widely spread in the environment, mainly in soils. Trichoderma are filamentous fungi and are used in a wide range of fields to manage plant patho-genic fungi. They have proven to be effective biocontrol agents due to their high reproducibility, adaptability, efficient nutrient mobilization, ability to colonize the rhizosphere, significant inhibitory effects against phytopathogenic fungi, and efficacy in promoting plant growth. In the present study, the antagonist Trichoderma isolates were characterized from the soil of Abha region, Saudi Arabia. Methodology: Soil samples were collected from six locations of Abha, Saudi Arabia to isolate Trichoderma having the antagonistic potential against plant pathogenic fungi. The soil dilution plate method was used to isolate Trichoderma (Trichoderma Specific Medium (TSM)). Isolated Trichoderma were evaluated for their antagonistic potential against Fusarium oxysporum, Alternaria alternata and Helminthosporium rostratum. The antagonist activity was assessed by dual culture assay, and the effect of volatile metabolites and culture filtrate of Trichoderma. In addition, the effect of different temperature and salt concentrations on the growth of Trichoderma isolates were also evaluated. Results: The most potent Trichoderma species were identified by using ITS4 and ITS 5 primers. Total 48 Trichoderma isolates were isolated on (TSM) from the soil samples out of those six isolates were found to have antagonist potential against the tested plant pathogenic fungi. In general, Trichoderma strains A (1) 2.1 T, A (3) 3.1 T and A (6) 2.2 T were found to be highly effective in reducing the growth of tested plant pathogenic fungi. Trichoderma A (1) 2.1 T was highly effective against F. oxysporum (82%), whereas Trichoderma A (6) 2.2 T prevented the maximal growth of H. rostratum (77%) according to the dual culture data. Furthermore, Trichoderma A (1) 2.1 T volatile metabolites hindered F. oxysporum growth. The volatile metabolite of Trichoderma A (6) 2.2 T, on the other hand, had the strongest activity against A. alternata (45%). The Trichoderma A (1) 2.1 T culture filtrate was proven to be effective in suppressing the growth of H. rostratum (47%). The temperature range of 26 °C to 30 °C was observed to be optimum for Trichoderma growth. Trichoderma isolates grew well at salt concentrations (NaCl) of 2%, and with the increasing salt concentration the growth of isolates decreased. The molecular analysis of potent fungi by ITS4 and ITS5 primers confirmed that the Trichoderma isolates A (1) 2.1 T, A (3) 3.1 and A (6) 2.2 T were T. harzianum, T. brevicompactum, and T. velutinum, respectively. Conclusions: The study concludes that the soil of the Abha region contains a large population of diverse fungi including Trichoderma, which can be explored further to be used as biocontrol agents.
Docking, Binding Free Energy Calculations and In Vitro Characterization of Pyrazine Linked 2-Aminobenzamides as Novel Class I Histone Deacetylase (HDAC) Inhibitors
Authors: Bülbül Emre F. , Melesina Jelena , Ibrahim Hany S. , Abdelsalam Mohamed , Vecchio Anita , Robaa Dina , Zessin Matthes , Schutkowski Mike , Sippl Wolfgang
Published: April 2022

Class I histone deacetylases, HDAC1, HDAC2, and HDAC3, represent potential targets for cancer treatment. However, the development of isoform-selective drugs for these enzymes remains challenging due to their high sequence and structural similarity. In the current study, we applied a computational approach to predict the selectivity profile of developed inhibitors. Molecular docking followed by MD simulation and calculation of binding free energy was performed for a dataset of 2-aminobenzamides comprising 30 previously developed inhibitors. For each HDAC isoform, a significant correlation was found between the binding free energy values and in vitro inhibitory activities. The predictive accuracy and reliability of the best preforming models were assessed on an external test set of newly designed and synthesized inhibitors. The developed binding free-energy models are cost-effective methods and help to reduce the time required to prioritize compounds for further studies.
Fixed-Bed Adsorption: Comparisons of Virgin and Zirconium Oxide-Coated Scoria for the Removal of Fluoride from Water
Authors: Geleta Wondwosen Sime , Alemayehu Esayas , Lennartz Bernd
Published: April 2022

Many people worldwide are exposed to extreme levels of fluoride in drinking water. It is, therefore, critical to develop inexpensive, locally available, and environmentally friendly adsorbents for fluoride-laden water defluoridation. In the current study, virgin scoria (volcanic rock) from Ethiopia, was modified with zirconium oxide and used as an adsorbent in a fixed-bed column aiming at the removal of fluoride from water. The adsorption capability of zirconium oxide-coated scoria (ZrOCSc) was compared with unmodified virgin scoria (VSco). XRD, FTIR, XRF, SEM, ICP-OES, and the pHPZC tests were evaluated to explore the adsorption mechanisms. Thermal analysis of VSco and ZrOCSc revealed lower total weight losses of 2.3 and 3.2 percent, respectively, owing to the removal of water molecules and OH species linked to metal oxides contained in the material. The effect of test conditions such as the pH of the solution and the influent flow rate on the adsorption capacity of the adsorbent was carefully studied. ZrOCSc exhibited the maximum removal capacity of 58 mg/kg, which was 4.46 times higher than the observations for VSco (13 mg/kg) at pH 2, and an initial flow rate of 1.25 mL/min. Breakthrough time increased with decreasing initial pH and flow rate. The adsorption experimental data under various test conditions were examined by the Thomas and Adams–Bohart models. Both models were found very effective in describing the experimental data with a correlation coefficient (R2) of ≥0.976 (ZrOCSc) and ≥0.967 (VSco). Generally, coating VSco with zirconium oxide improved the adsorption performance of VSco; hence, a ZrOCSc-packed fixed bed could be employed for the decontamination of high levels of fluoride from groundwater. However, further examination of the adsorbent using natural groundwater is advisable to produce a definitive conclusion.
Stereoselective Synthesis of β-Glycinamide Ribonucleotide
Authors: Ngu Lisa , Ray Debarpita , Watson Samantha S. , Beuning Penny J. , Ondrechen Mary Jo , O’Doherty George A.
Published: April 2022

A diastereoselective synthesis of the β-anomer of glycinamide ribonucleotide (β-GAR) has been developed. The synthesis was accomplished in nine steps from D-ribose and occurred in 5% overall yield. The route provided material on the multi-milligram scale. The synthetic β-GAR formed was remarkably resistant to anomerization both in solution and as a solid.
Light-Activated Monomethyl Auristatin E Prodrug Nanoparticles for Combinational Photo-Chemotherapy of Pancreatic Cancer
Authors: Cho In Kyung , Shim Man Kyu , Um Wooram , Kim Jong-Ho , Kim Kwangmeyung
Published: April 2022

Pancreatic cancer is a highly fatal disease that is becoming an increasingly leading cause of cancer-related deaths. In clinic, the most effective approach to treat pancreatic cancers is the combination treatment of several chemotherapeutic drugs, including fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX), but this approach is not adequate to manage patients due to their severe toxic side effects. Herein, we proposed light-activated monomethyl auristatin E (MMAE) prodrug nanoparticles for combinational photo-chemotherapy and optimized its applications for pancreatic cancer treatment. The photosensitizer (Ce6) and chemotherapeutic drug (MMAE) were conjugated through caspase-3-specific cleavable peptide (KGDEVD). The resulting CDM efficiently promoted the reactive oxygen species (ROS) under visible light irradiation and thereby induced caspase-3 overexpression in pacreatic cancers, which subsequently released the MMAE from the system. Importantly, MMAE released from CDM further amplified the activation of CDM into MMAE by inducing extensive apoptotic cell death in tumor microenvironment for treatment of tumor cells in deep in the tumor tissues as far visible light cannot reach. In addition, CDM formed prodrug nanoparticles via intermolecular π-π stacking and hydrophobic interactions, allowing durable and reliable treatment by preventing fast leakage from the pancreatic cancers via the lymphatic vessels. The CDM directly (intratumoral) injected into pancreatic cancers in orthotopic models through an invasive approach significantly delayed the tumor progression by combinational photo-chemotherapy with less toxic side effects. This study offers a promising and alternative approach for safe and more effective pancreatic cancer treatment via prodrug nanoparticles that combine photodynamic therapy and chemotherapy.
Geochemical Characteristics and Significance of Organic Matter in Hydrate-Bearing Sediments from Shenhu Area, South China Sea
Authors: Li Yuanyuan , Pang Lei , Wang Zuodong , Meng Qianxiang , Guan Ping , Xu Xuemin , Fang Yunxin , Lu Hailong , Ye Jianliang , Xie Wenwei
Published: April 2022

Rock-Eval pyrolysis and the biomarker composition of organic matter were systematically studied in hydrate-bearing sediments from the Shenhu area, South China Sea. The n-alkane distribution patterns revealed that the organic matter in the sediments appeared to originate from mixed sources of marine autochthonous input, terrestrial higher plants, and ancient reworked organic matter. The low total organic carbon contents (average < 0.5%) and the low hydrogen index (HI, <80 mg HC/g TOC) suggested the poor hydrocarbon-generation potential of the deposited organic matter at a surrounding temperature of <20 °C in unconsolidated sediments. The abnormally high production index and the fossil-originated unresolved complex mixture (UCM) accompanied by sterane and hopane of high maturity indicated the contribution of deep hydrocarbon reservoirs. Preliminary oil-to-source correlation for the extracts implied that the allochthonous hydrocarbons in the W01B and W02B sediments might have originated from the terrestrial source rocks of mature Enping and Wenchang formations, while those of W03B seem to be derived from more reduced and immature marine source rocks such as the Zhuhai formation. The results of the organic extracts supported the previous identification of source rocks based on the isotopic composition of C2+ hydrate-bound gases. The biomarker of methanogens, squalane, was recognized in the sediments of this study, possibly suggesting the generation of secondary microbial gases which are coupled with the biodegradation of the deep allochthonous hydrocarbons.
Hydrolytic vs. Nonhydrolytic Sol-Gel in Preparation of Mixed Oxide Silica–Alumina Catalysts for Esterification
Authors: Al Khudhair Atheer , Bouchmella Karim , Mutin Pierre Hubert , Hulea Vasile , Gimello Olinda , Mehdi Ahmad
Published: April 2022

The development of green and sustainable materials for use as heterogeneous catalysts is a growing area of research in chemistry. In this paper, mesoporous SiO2-Al2O3 mixed oxide catalysts with different Si/Al ratios were prepared via hydrolytic (HSG) and nonhydrolytic sol-gel (NHSG) processes. The HSG route was explored in acidic and basic media, while NHSG was investigated in the presence of diisopropylether as an oxygen donor. The obtained materials were characterized using EDX, N2-physisorption, powder XRD, 29Si, 27Al MAS-NMR, and NH3-TPD. This approach offered good control of composition and the Si/Al ratio was found to influence both the texture and the acidity of the mesoporous materials. According to 27Al and 29Si MAS NMR analyses, silicon and aluminum were more regularly distributed in NHSG samples that were also more acidic. Silica–alumina catalysts prepared via NHSG were more active in esterification of acetic acid with n-BuOH.
Free Amino Acids and Volatile Aroma Compounds in Watermelon Rind, Flesh, and Three Rind-Flesh Juices
Authors: Du Xiaofen , Davila Mindy , Ramirez Jessica , Williams Cierra
Published: April 2022

Watermelon rind is treated as agricultural waste, causing biomass loss and environmental issues. This study aimed to identify free amino acids and volatiles in watermelon rind, flesh, and rind-flesh juice blends with ratios of 10%, 20%, and 30%. Among the 16 free amino acids quantified, watermelon rind alone contained higher total amino acids (165 mg/100 g fresh weight) compared to flesh alone (146 mg/100 g). The rind had significantly higher (1.5×) and dominant amounts of citrulline and arginine (61.4 and 53.8 mg/100 g, respectively) than flesh. The rind, however, contained significantly lower amounts of essential amino acids. Volatile analysis showed that watermelon rind total volatiles (peak area) comprised only 15% of the flesh volatiles. Of the 126 volatiles identified, the rind alone contained 77 compounds; 56 of these presented in all five samples. Aldehydes and alcohols were most prevalent, accounting for >80% of the total volatiles in all samples. Nine-carbon aldehyde and alcohol compounds dominated both the flesh and rind, though the rind lacked the diversity of other aldehydes, alcohols, ketones, terpenes, terpenoids, esters and lactones that were more abundant in the watermelon flesh. Watermelon rind was characterized by the major aroma compounds above their thresholds, including 17 aldehydes and six unsaturated nine-carbon alcohols. This study demonstrated the potential for rind as a food or beverage supplement due to its key features such as concentrated citrulline and arginine, relatively low odor intensity, and valuable volatiles associated with fresh, green, cucumber-like aromas.
Detection, Identification and Size Distribution of Silver Nanoparticles (AgNPs) in Milk and Migration Study for Breast Milk Storage Bags
Authors: Li Bin , Chua Sew Lay , Yu Dingyi , Chan Sheot Harn , Li Angela
Published: April 2022

The engineered silver nanoparticles (AgNPs) have been widely used in various food contact materials (FCMs) based on their antibacterial properties. This widespread use of nanosilver has, however, increased the risk of exposure of AgNPs to human due to their migration from FCMs causing a potential hazard present in foods. Therefore, it is important to establish a reliable and practical method for the detection of AgNPs in food matrices to support risk assessment on AgNPs exposure. Taking the examples of milk and AgNPs-containing breast milk storage bags, this study established an approach for size characterization and quantification of AgNPs in milk and evaluated the relevant silver migration, based on enzymatic digestion and the analysis by asymmetric flow field–flow fractionation (AF4) hyphenated with inductively coupled plasma mass spectrometry (ICP-MS) and single particle inductively coupled plasma mass spectrometry (SP-ICP-MS). No migration of AgNPs was found from breast milk storage bags under various simulated storage conditions as well as extreme scenarios. The suitability and reliability of this method were also validated by the determination of multiple parameters, including accuracy, repeatability, limit of detection (LOD), limit of quantification (LOQ), and recovery, for AF4-ICP-MS and SP-ICP-MS, respectively, with good and overall acceptable evaluation results obtained for all. The established and validated approach was demonstrated to be suitable for the characterization and quantitation of AgNPs in milk as well as the analysis of their migration from breast milk storage bags.
Identification of Novel Covalent XPO1 Inhibitors Based on a Hybrid Virtual Screening Strategy
Authors: Shen Zheyuan , Zhuang Weihao , Li Kang , Guo Yu , Qu Bingxue , Chen Sikang , Gao Jian , Liu Jing , Xu Lei , Dong Xiaowu , Che Jinxin , Li Qimeng
Published: April 2022

Nuclear export protein 1 (XPO1), a member of the nuclear export protein-p (Karyopherin-P) superfamily, regulates the transport of “cargo” proteins. To facilitate this important process, which is essential for cellular homeostasis, XPO1 must first recognize and bind the cargo proteins. To inhibit this process, small molecule inhibitors have been designed that inhibit XPO1 activity through covalent binding. However, the scaffolds for these inhibitors are very limited. While virtual screening may be used to expand the diversity of the XPO1 inhibitor skeleton, enormous computational resources would be required to accomplish this using traditional screening methods. In the present study, we report the development of a hybrid virtual screening workflow and its application in XPO1 covalent inhibitor screening. After screening, several promising XPO1 covalent molecules were obtained. Of these, compound 8 performed well in both tumor cell proliferation assays and a nuclear export inhibition assay. In addition, molecular dynamics simulations were performed to provide information on the mode of interaction of compound 8 with XPO1. This research has identified a promising new scaffold for XPO1 inhibitors, and it demonstrates an effective and resource-saving workflow for identifying new covalent inhibitors.
Effects of Sphingomyelin-Containing Milk Phospholipids on Skin Hydration in UVB-Exposed Hairless Mice
Authors: Ahn Yejin , Kim Min Guk , Jo Kyungae , Hong Ki-Bae , Suh Hyung Joo
Published: April 2022

Reactive oxygen species (ROS) generated by ultraviolet (UV) exposure cause skin barrier dysfunction, which leads to dry skin. In this study, the skin moisturizing effect of sphingomyelin-containing milk phospholipids in UV-induced hairless mice was evaluated. Hairless mice were irradiated with UVB for eight weeks, and milk phospholipids (50, 100, and 150 mg/kg) were administered daily. Milk phospholipids suppressed UV-induced increase in erythema and skin thickness, decreased transepidermal water loss, and increased skin moisture. Milk phospholipids increased the expression of filaggrin, involucrin, and aquaporin3 (AQP3), which are skin moisture-related factors. Additionally, hyaluronic acid (HA) content in the skin tissue was maintained by regulating the expression of HA synthesis- and degradation-related enzymes. Milk phospholipids alleviated UV-induced decrease in the expression of the antioxidant enzymes superoxidase dismutase1 and 2, catalase, and glutathione peroxidase1. Moreover, ROS levels were reduced by regulating heme oxygenase-1 (HO-1), an ROS regulator, through milk phospholipid-mediated activation of nuclear factor erythroid-2-related factor 2 (Nrf2). Collectively, sphingomyelin-containing milk phospholipids contributed to moisturizing the skin by maintaining HA content and reducing ROS levels in UVB-irradiated hairless mice, thereby, minimizing damage to the skin barrier caused by photoaging.
Layering Optimization of the SrFe0.9Ti0.1O3−δ–Ce0.8Sm0.2O1.9 Composite Cathode
Authors: Abd Aziz Azreen , Baharuddin Nurul , Somalu Mahendra , Muchtar Andanastuti
Published: April 2022

Cathode thickness plays a major role in establishing an active area for an oxygen reduction reaction in energy converter devices, such as solid oxide fuel cells. In this work, we prepared SrFe0.9Ti0.1O3−δ–Ce0.8Sm0.2O1.9 composite cathodes with different layers (1×, 3×, 5×, 7×, and 9× layer). The microstructural and electrochemical performance of each cell was then explored through scanning electron microscopy and electrochemical impedance spectroscopy (EIS). EIS analysis showed that the area-specific resistance (ASR) decreased from 0.65 Ωcm2 to 0.12 Ωcm2 with the increase in the number of layers from a 1× to a 7×. However, the ASR started to slightly increase at the 9× layer to 2.95 Ωcm2 due to a higher loss of electrode polarization resulting from insufficient gas diffusion and transport. Therefore, increasing the number of cathode layers could increase the performance of the cathode by enlarging the active area for the reaction up to the threshold point.
The Potential Use of Herbal Fingerprints by Means of HPLC and TLC for Characterization and Identification of Herbal Extracts and the Distinction of Latvian Native Medicinal Plants
Authors: Bārzdiņa Ance , Paulausks Artūrs , Bandere Dace , Brangule Agnese
Published: April 2022

The growing market of herbal medicines, the increase in international trade in Latvia, and the lack of adequate analytical methods have raised the question of the potential use of herbal fingerprinting methods. In this study, high-performance liquid chromatography (HPLC) and thin layer chromatography (TLC) methods were developed for obtaining chromatographic fingerprints of four taxonomically and evolutionary different medicinal plants (Hibiscus sabdariffa L., Calendula officinalis L., Matricaria recutita L., Achillea millefolium L.). Retention time shifting, principal component analysis (PCA), hierarchical cluster analysis (HCA), and orthogonal projections to latent structures (OPLS) analysis were used to improve and analyze the obtained fingerprints. HPLC data detection at 270 nm was determined superior to 360 nm for the distinction of medicinal plants and used data alignment method significantly increased similarity between samples. Analyzed medicinal plant extracts formed separate, compact clusters in PCA, and the results of HCA correlated with the evolutionary relationships of the analyzed medicinal plants. Herbal fingerprinting using chromatographic analysis coupled with multivariate analysis has a great potential for the identification of medicinal plants as well as for the distinction of Latvian native medicinal plants.
Properties of Rice-Based Beverages Fermented with Lactic Acid Bacteria and Propionibacterium
Authors: Cichońska Patrycja , Ziębicka Anna , Ziarno Małgorzata
Published: April 2022

In recent times, consumers have shown increasing interest in plant substitutes for fermented dairy products. This study aimed to investigate the properties of yogurt-type rice-based beverages fermented with lactic acid bacteria and Propionibacterium. The changes in pH, viable population of bacteria, physical properties, and carbohydrate content of these beverages were tested. Fermentation using only Propionibacterium was insufficient to obtain a product with an acidity level similar to that of milk-based yogurt (pH < 4.5). After fermentation, the tested beverages had a high number of Lactobacillus sp. (7.42–8.23 log10 CFU/mL), Streptococcus thermophilus (8.01–8.65 log10 CFU/mL), and Bifidobacterium animalis subsp. lactis (8.28–8.50 log10 CFU/mL). The hardness (2.90–10.40 N) and adhesiveness (13.79–42.16 mJ) of the samples after 14 days of storage at 6 °C varied depending on the starter culture used. The syneresis of all samples ranged between 29% and 31%, which was lower or close to that of milk-based yogurts. The content of individual sugars in the samples also varied depending on the starter culture used for fermentation. The results suggest that the combination of lactic and propionic fermentation helps in the production of rice-based yogurt-type milk substitutes.