Changes In Chemical Composition Research Articles

Effect of Electrolytic Plasma Polishing on Surface Properties of Titanium Alloy

Effect of Electrolytic Plasma Polishing on Surface Properties of Titanium Alloy

Performance evolution and mechanism of asphalt crack sealant under UV aging: A continuity study

Asphalt crack repair materials, known as crack sealants, are directly exposed to ultraviolet (UV) radiation in asphalt pavements. This exposure causes the gradual aging and deterioration of both their surface and internal properties. To study this phenomenon, the sealant was subjected to UV irradiation for a range of 0–385 hours, with the basic properties of the aged sealant tested every 55 hours. Several techniques were employed to investigate the changes in the internal chemical composition of the sealant, including Fluorescence microscopy (FM), gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FT-IR). The results revealed that the UV aging of the sealant mainly occurs in the thinner surface layer, which becomes progressively lighter in color. Notably, obvious surface cracks form after aging process. The cone penetration and softening point of the sealant exhibit an exponential or logarithmic change corresponding to the aging time. The most pronounced changes occur during the early stages of UV aging, with the properties tending to stabilize after approximately 220 h of aging. In addition, the FM images showed that the dispersed polymer particles within the sealant gradually transform into a continuous network structure after aging over time. The GPC spectrum of the aged sealant shifts to the left, indicating an increase in molecular weight, particularly in the polymer modifier. This is consistent with the transformation observed in the FT-IR analysis, which demonstrates that UV irradiation leads to the breaking and recombination of polymer chemical bonds in the sealant. The FT-IR analysis reveals the conversion of monosubstituted benzene to polysubstituted benzene in the polymer modifier, which also correlates with the formation of the network structure observed in the FM images and the increase in molecular weight detected in the GPC spectrum of the polymer modifier.

Biodegradation effects of three Aspergillus species on iron-based oxides (Hematite − Goethite) in paint layer in oil paintings

The inorganic colour layer based on iron oxide is affected by microorganisms (fungi) and leads to its deterioration due to feeding on the mineral elements through the chemical composition of the colour in the presence of a suitable environment (medium). Damage occurs as a result of heavy metal elements being removed from the colour, leading to a defect in the chemical composition and the fading of the colours. The current study showed the effect of the different types of the most common fungi on oil paintings (Aspergillus flavius, Aspergillus fumigatus and Aspergillus niger) after cultivating the different types of fungi and obtaining pure colonies for each fungus separately and conducting a fungal infection on experimental samples with preparing the old techniques, coloured with hematite red and goethite yellow. Each colour is mixed with different proportions of linseed oil (1, 2, 3). They were aged artificially and incubated at a temperature of 262+- degrees and examined periodically until the fungi appeared on the surface in the form of colour spots ranging from very dark (severe infestation) to light (low infestation). The change in chemical composition was measured by Raman and EDX analyses of the samples before and after infection. Fungi showed the appearance of spoilage products from metal sulfides and metal carboxylates. The iron oxide ion decreased in both the red and the yellow colours, leading to a change after the fungal infection. Examination of the morphological surface using SEM, USB and measurement of colour change showed the change in the red colour more than the yellow and scattering of green and black colour dots on the surface of the sample. Correlation and Simple Linear Regression were applied for each colour before and after besides both colours together. It was found that these colours appeared around some of the fungal colonies as a result of the activities. Fungal species of some strains reduced Fe+3 to Fe+2. This provides new insights into the role of microorganisms in the deterioration of painted surfaces.

The synergistic potential of orange peel extract: A comprehensive investigation into its phenolic composition, antioxidant, antimicrobial, and functional fortification properties in yogurt

The study explores the potential of orange peel extract (OPE) as a versatile natural resource, focusing on its phenolic composition, antioxidant, and antibacterial properties, as well as its application in fortifying yogurt. Analysis revealed significant concentrations of phenolic compounds in OPE. OPE exhibited notable antibacterial efficacy against pathogenic bacteria, particularly marine Escherichia coli, with synergistic effects observed when combined with Amikacin. Incorporating OPE into yogurt led to changes in chemical composition, enhancing total proteins, fat, and ash content. Fortified yogurt showed increased antioxidant activity and potential anti-cancer properties against HCT116 cell lines. In conclusion, OPE emerges as a rich source of bioactive compounds with diverse applications, from its antioxidant and antibacterial properties to its potential in fortifying functional foods like yogurt. This comprehensive exploration provides valuable insights into the multifaceted benefits of OPE, paving the way for its utilization in various industries and health-related applications.

Quality evaluation and identification of Houttuynia cordata bleached with sodium metabisulfite based on whole spectrum metabolomics

Houttuynia Cordata (HC) is a widely distributed plant in Asia and is used extensively for both food and medicinal purposes. A preliminary investigation found that HC is often bleached with sodium metabisulfite solution during its field processing, leading to health risks. In this study, the effects of sodium metabisulfite on the quality of HC were comprehensively evaluated using volatile and non-volatile targeted metabolomic methods. The results revealed a positive correlation between the extent of chemical composition changes and the bleaching time. These notable changes mainly occurred at the initial stage of bleaching. Subsequently, an untargeted UPLC/Q-TOF MS method was used to explore the potential chemical bleaching markers in bleached HC. The marker 1-hydroxy-3-oxodecane-1-sulfonic acid was subsequently prepared, isolated, and identified. Market sample verification further validated the accuracy and effectiveness of this marker.

Winter monsoon brings substantial terrestrial aerosols to Bay of Bengal and adjacent Indian Ocean: Insights from carbon and nitrogen isotopes

It has been currently recognized that air pollutants (e.g., carbon and nitrogen) from South and Southeast Asia have a significant impact on the coastal waters of the northern Indian Ocean. However, the understanding of dynamics and fates of these pollutants in aerosols to the remote ocean through long-distance transportation still needs to be improved. To address this issue, stable isotopic compositions (δ13C, δ15N) of total carbon (TC) and nitrogen (TN) and other geochemical indexes in aerosols are investigated over the Bay of Bengal (BOB) and the adjacent Indian Ocean during the winter monsoon period. The concentrations of TN, TC and aerosol nutrients exhibited a decreasing trend from the northern BOB (N-BOB) to the southern BOB (S-BOB) and Indian Ocean, reflecting the weakening trend of polluted continental influence from the N-BOB to the ocean. The high concentrations of TC (4.28–18.21 μg m−3) in the aerosols of the N-BOB were mainly influenced by the emissions of coal combustion (68 ± 21%), while the high concentrations of TN (0.69–7.31 μg m−3) in the N-BOB were mainly from biofuel/biomass burning (52 ± 31%). In the S-BOB, the lower concentrations of TC (1.42–2.98 μg m−3) and TN (0.38–2.03 μg m−3) mainly originated from the formation of secondary aerosols and the changes in aerosol chemical composition during long-distance transportation from the continent. The primary marine source was responsible for the low TC and TN concentrations over the Indian Ocean. This study quantifies the nitrogen and carbon source shifts from continental anthropogenic activities in the N-BOB to dominant marine and photochemical transformation sources in the remote ocean, quantitatively deepening the understanding of the impact of terrestrial aerosols on the ocean.

High-performance grating-like SERS substrate based on machine learning for ultrasensitive detection of Zexie-Baizhu decoction

Rapid, universal and accurate identification of chemical composition changes in multi-component traditional Chinese medicine (TCM) decoction is a necessary condition for elucidating the effectiveness and mechanism of pharmacodynamic substances in TCM. In this paper, SERS technology, combined with grating-like SERS substrate and machine learning method, was used to establish an efficient and sensitive method for the detection of TCM decoction. Firstly, the grating-like substrate prepared by magnetron sputtering technology was served as a reliable SERS sensor for the identification of TCM decoction. The enhancement factor (EF) of 4-ATP probe molecules was as high as 1.90 × 107 and the limit of detection (LOD) was as low as 1 × 10−10 M. Then, SERS technology combined with support vector machine (SVM), decision tree (DT), Naive Bayes (NB) and other machine learning algorithms were used to classify and identify the three TCM decoctions, and the classification accuracy rate was as high as 97.78 %. In summary, it is expected that the proposed method combining SERS and machine learning method will have a high development in the practical application of multi-component analytes in TCM.

Acid attack on hydrated cement: effect of organic acids on the degradation process

Owing to their ability to form buffer solutions, the attack of organic acids on concrete structural components can be highly aggressive. This work considers the changes in microstructure, chemical and phase composition in hardened Portland cement paste (hcp) exposed to acetic acid/sodium acetate or citric acid/sodium citrate buffer solutions. The degradation products were investigated using 29Si and 27Al NMR spectroscopy with XRD and ICP-OES. Exposure to acetic acid/sodium acetate at pH 3.9 ≤ pH ≤ 5.5 decalcifies hcp to produce aluminosilica gels (0.1 ≤ Al/Si ≤ 0.3) with Si predominately in Q3/Q4 sites and NBO values (non-bridging oxygen per Si atom) 0.6 ≤ NBO ≤ 0.9. Cross-linking processes causing the formation of the gel from C–A–S–H dreierketten incorporate Al, originally in crystalline phases and C–A–S–H phases. Degradation by citric acid/sodium citrate is governed by the precipitation of expansive calcium citrate which continuously removes degraded surface material. Pore-blocking at the degradation front inhibits acid transport deeper into the material. A new mathematical expression is presented which enables the calculation of NBO for aluminosilica gels of known Al/Si ratio from 29Si NMR spectra despite overlapping signals. The expression was verified by a stochastic computer model based on a Si quartz lattice with substituted Al and vacancies. The model simulated the measured 29Si NMR spectra of aluminosilica gels.

Electrocatalytic properties of Ni–Cu structures fabricated by electrodeposition of Cu on Ni cones

Ni–Cu alloys are a suitable candidate as a catalyst in Hydrogen Evolution Reaction due to their catalytic performance and good stability. To enhance this activity more, the active surface area of the material should be enhanced. It is commonly achieved by the synthesis of metals and alloys in the form of nanostructures. In this work, Ni cones fabricated by the one-step method were applied as a substrate for the deposition of thin Cu layers. Then, these materials were annealed in an ambient atmosphere to obtain Ni–Cu structures. The investigation of changes in morphology and chemical composition, as well as roughness and wettability before and after the annealing process was performed. Moreover, the measurements of catalytic properties were carried out in 1 M NaOH. The values of the Tafel slope and the electrochemical active surface area were studied. The proposed method can be successfully applied to fabricate structures of other alloys for the desired properties.

Tailoring surface properties of Poly(caprolactone)/Hydroxyapatite scaffolds through aminolysis and multi-walled carbon nanotube coating for bone tissue engineering

In this study, the effects of surface modification on the physicochemical properties, degradation behavior, and cellular responses of poly(caprolactone) (PCL)/hydroxyapatite (HAp) scaffolds using carboxylated multi-walled carbon nanotubes (MWCNTs) were investigated. The scaffolds were prepared using the fused deposition modeling (FDM) technique, followed by aminolysis for 15, 30, and 60 minutes. Subsequently, the scaffolds were immersed in MWCNT solutions with concentrations of 0.1 %, 0.5 %, and 1 % g/mL to achieve the desired coating. Various characterization techniques were employed to evaluate the surface morphology, chemical composition, and structural changes induced by the coating. FESEM images revealed a uniform MWCNT coating on the PCL/HAp scaffolds at an optimal concentration of 0.5 % g/mL, while lower concentrations resulted in incomplete coating and higher concentrations led to MWCNT agglomerations. The MWCNT coating successfully enhanced the conductivity of the scaffolds, with electrical conductivity increasing from near zero for the non-coated PCL/HAp scaffolds to 5 × 10−5 S/m for the MWCNT-coated scaffolds. Additionally, the coating exhibited improved wettability, as demonstrated by decreased water contact angles from 67.71° for non-coated surfaces to 51.50° for the MWCNT-coated surfaces. Furthermore, the in vitro degradation studies showed that HAp in the PCL matrix accelerated the hydrolysis rate, resulting in higher degradation rates for the PCL/HAp scaffolds than pure PCL scaffolds. The MWCNT coating further influenced the degradation behavior, with variations in degradation rates depending on the MWCNT concentration. Cell viability assays using MG-63 cells revealed improved cell viability and adhesion on the MWCNT-coated PCL/HAp scaffolds compared to plain PCL and PCL/HAp scaffolds. The cell viability increased from 84 % for plain PCL and 103 % for PCL/HAp to 109 % for the MWCNT-coated scaffolds. Moreover, FESEM images showed increased cell adhesion on the MWCNT-coated surfaces, with optimal adhesion observed on the scaffolds coated with 0.5 % g/mL MWCNTs. The results of this study highlight the potential of MWCNT coatings to improve the surface properties of PCL/HAp scaffolds, making them excellent choices for bone tissue engineering applications.

Microstructural Investigations of Weld Deposits from Manganese Austenitic Alloy on X2CrNiMoN22-5-3 Duplex Stainless Steel

Duplex stainless steels are materials with high performance under mechanical stress and stress corrosion in chloride ion environments. Despite being used in many new applications such as components for offshore drilling platforms as well as in the chemical and petrochemical industry, the automotive industry, etc., they face issues of wear and hardness that limit current applications and prevent the creation of new use opportunities. To address these shortcomings, it is proposed to develop a hardfacing process by a special welding technique using a universal TIG source adapted for manual welding with a pulsed current, and a manganese austenitic alloy electrode as filler material. The opportunity to deposit layers of manganese austenitic steel through welding creates advantages related to the possibility of achieving high mechanical characteristics of this steel exclusively in the working area of the part, while the substrate material will not undergo significant changes in chemical composition. As a result of the high strain hardening rate, assisted mainly by mechanical twinning, manganese austenitic alloys having a face-centered cubic crystal lattice (f.c.c) and low stacking fault energy (SFE = 20–40 mJ/m2) at room temperature, exhibit high wear resistance and exceptional toughness. Following cold deformation, the hardness of the deposited metal increases to 465 HV5–490 HV5. The microstructural characteristics were investigated through optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and Vickers hardness measurements (HV). The obtained results highlighted the feasibility of forming hard coatings on duplex stainless steel substrates.

Corrosion of Zinc Cold Spray Coatings in a Wet Sweet and Sour Gas Environment.

ABSTRACT Internal corrosion is a problem for steel pipelines transporting natural gas or CO2 containing water and partial pressures of H2S higher than 0.3 kPa (0.05 psi). This work aims to mitigate internal corrosion in steel pipelines transporting natural gas containing H2S using cold spray coatings. Two types of the cold spray binary metallic coatings (zinc chromium (ZnCr), zinc niobium (ZnNb)) were studied using electrochemical techniques: potentiodynamic polarization (PDP), linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS). The corrosion resistance of cold spray coatings (ZnCr, ZnNb) was evaluated in an environment containing 4 bar CO2 pressure, simulating the partial pressures found in gas transmission lines over a solution of 3.5 wt.% NaCl heated to 40 °C. A concentration of 0.003 M Na2S2O3.5H2O, which corresponds to H2S partial pressures around 0.079 bar (1.146 psi), was used to simulate sour conditions. Post-corrosion surface characterization was performed using a scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscope (EDS) and X-ray diffraction analysis (XRD). The data showed that the presence of 0.003 M Na2S2O3.5H2O shifted the corrosion potential to more anodic values and decreased the corrosion current density. Both coatings showed similar behavior after 1 hour of exposure in the CO2/H2S environment, indicating that similar electrochemical reactions were occurring on ZnNb and ZnCr. SEM images and EDS surface analyses for specimens showed a significant change in the surface chemical composition of carbon steel coated with ZnNb and ZnCr after 24 hours of immersion. In the presence of thiosulfate (under sour conditions), the formation of corrosion product layers (ZnCO3 and ZnS) on top of ZnNb and ZnCr coatings increased their corrosion resistance, which helped to reduce their corrosion by a factor of 2. Under a sweet environment. The corrosion rates for steel coated with cold spray coatings after 14 days of exposure are lower than that for galvanized steel by a factor of 5 due to the ZnCO3 layer formed on top of the coatings. The ZnCO3 layer formed on the steel surface acts as a physical barrier against corrosion by blocking the diffusion of corrosive species to the surface. No localized attack was observed. ZnCr Cold spray coating with defect showed promising corrosion protection against CO2 corrosion (sweet corrosion) after 14 days of exposure to a CO2 environment. The scratch on the coating simulated damage created in service, and it was deep enough to expose the substrate material (steel). The formation of zinc oxide (ZnO) and zinc carbonate (ZnCO3) on the scratch confirmed the cathodic protection of the steel by ZnCr and ZnNb coatings.

Differences in Airway Remodeling and Emphysematous Lesions between Rats Exposed to Smoke from New-Type and Conventional Tobacco Varieties

Genes from Perilla frutescens and Ocimum basilicum were introduced into N. tabacum L. var. HHY via distant hybridization, and the new-type tobacco varieties “Zisu” and “Luole” were developed, with noticeable differences in chemical composition. Smoking is the leading cause of chronic obstructive pulmonary disease (COPD), and its pathogenesis is complex. In the present study, 48 male Sprague-Dawley (SD) rats were randomly divided into four groups, namely, the control, “HHY”, “Zisu” and “Luole”, and then exposed to fresh air/cigarette smoke (CS) for 30 days and 60 days. The COPD model was constructed, and their health hazards were compared and evaluated. CS from different tobacco varieties influenced rats in varying degrees at the tissue, cell and molecular levels. The rats in the “HHY” group showed obvious symptoms, such as cough and dyspnea, which were less severe in the “Zisu” and “Luole” groups. Pathological and morphological analyses, including scores, MLI, MAN, WAt/Pbm and WAm/Pbm, showed that “Zisu” and “Luole” caused less damage to the airways and lung parenchyma than “HHY”. Significant increases in the numbers of total leukocytes and neutrophils in the BALF were found in “HHY” compared to those in “Zisu” and “Luole”. Moreover, they caused less oxidative stress and apoptosis in lung tissues, as reflected by indicators such as ROS, MDA, T-AOC, GSH, the apoptotic index and the ratio of Bcl-2 to Bax. “Zisu” and “Luole” even altered the ratios of MMP-9/TIMP-1 and IFN-γ/IL-4 in lung tissues to a lesser degree. These differences between CS-exposed rats may be closely related to the altered expression of Nrf2, p38 MAPK and p-p38 MAPK. Changes in chemical composition via introducing genes from some medicinal plants may be an attractive strategy for tobacco harm reduction.

Changes in chemical composition of TixAl1−xN coatings immersed in oxygen-saturated Lead–Bismuth Eutectic at low and moderate temperatures (250 °C ≤ T ≤ 410 °C)

Lead–Bismuth Eutectic (LBE) will serve as a liquid metal coolant in accelerator-driven systems, posing a corrosive threat to exposed materials. To address this challenge, TixAl1-xN coatings (0.38 ≤ x ≤ 0.58) were applied onto AISI 316 L austenitic stainless steel using the reactive bipolar magnetron sputtering technique. These coated samples underwent immersion in static oxygen-saturated LBE at temperatures of 250 °C and 360 °C for durations of 500 h and 1000 h, and at 410 °C for 500 h. XPS depth profiles revealed minimal oxidation at 250 °C even after 1000 h. However, at 360 °C, a mixed oxide layer of (Ti, Al)Ox was formed on the coating's surface. Exposure to LBE at 410 °C for 500 h led to the creation of an oxide bilayer comprising TiO2 (outer sublayer) and (Ti, Al)Ox depleted of Ti (inner sublayer). A model is proposed to illustrate the oxidation mechanism.

Changes in Chemical Composition of Lentils, Including Gamma-Aminobutyric Acid and Volatile Compound Formation during Submerged and Solid-State Fermentation with Pediococcus acidilactici.

The aim of this study was to evaluate and compare the characteristics of non-treated and fermented [via submerged (SMF) and solid-state (SSF) fermentation using Pediococcus acidilactici] lentils (Lens culinaris) grown either in pure stands (L) or relay intercropped with winter rye (LR). It was observed that the lentils were suitable substrate for lacto-fermentation. Most of the free amino acid concentrations increased in lentils after both fermentations. The highest concentration of γ-aminobutyric acid was found in SSF LR samples. However, fermentation led to higher biogenic amines (BA) content in lentils. The most abundant fatty acid in lentils was C18:2. SSF lentils showed more complex volatile compound (VC) profiles (with between nine and seventeen new VCs formed), whereas, in SMF samples, between two and five newly VCs were formed. When comparing lentil grown types, L contained significantly higher concentrations of Na, K, Ca, P, Mn, and Se, while LR contained significantly higher concentrations of Fe and Ni. To sum up, fermentation with lactic acid bacteria (LAB) contributed to the improved biological value of lentils; still, the quantity of BA needs to be considered. Further investigations into the P. acidilactici metabolism of certain compounds (such as phenolic and antinutritional compounds) in lentils during fermentation ought to be carried out.

Raman Imaging-A Valuable Tool for Tracking Fatty Acid Metabolism-Normal and Cancer Human Colon Single-Cell Study.

Altered metabolism of lipids is a key factor in many diseases including cancer. Therefore, investigations into the impact of unsaturated and saturated fatty acids (FAs) on human body homeostasis are crucial for understanding the development of lifestyle diseases. In this paper, we focus on the impact of palmitic (PA), linoleic (LA), and eicosapentaenoic (EPA) acids on human colon normal (CCD-18 Co) and cancer (Caco-2) single cells using Raman imaging and spectroscopy. The label-free nature of Raman imaging allowed us to evaluate FAs dynamics without modifying endogenous cellular metabolism. Thanks to the ability of Raman imaging to visualize single-cell substructures, we have analyzed the changes in chemical composition of endoplasmic reticulum (ER), mitochondria, lipid droplets (LDs), and nucleus upon FA supplementation. Analysis of Raman band intensity ratios typical for lipids, proteins, and nucleic acids (I1656/I1444, I1444/I1256, I1444/I750, I1304/I1256) proved that, using Raman mapping, we can observe the metabolic pathways of FAs in ER, which is responsible for the uptake of exogenous FAs, de novo synthesis, elongation, and desaturation of FAs, in mitochondria responsible for energy production via FA oxidation, in LDs specialized in cellular fat storage, and in the nucleus, where FAs are transported via fatty-acid-binding proteins, biomarkers of human colon cancerogenesis. Analysis for membranes showed that the uptake of FAs effectively changed the chemical composition of this organelle, and the strongest effect was noticed for LA. The spectroscopy studies have been completed using XTT tests, which showed that the addition of LA or EPA for Caco-2 cells decreases their viability with a stronger effect observed for LA and the opposite effect observed for PA. For normal cells, CCD-18 Co supplementation using LA or EPA stimulated cells for growing, while PA had the opposite impact.

Shot peening of AZ31 magnesium alloy: role of surface microstructure and iron diffusion on corrosion behaviour

ABSTRACT In the present work, surface grain refined AZ31 magnesium (Mg) alloy was produced by shot peening (SP). X-ray diffraction analysis demonstrated iron diffusion into the surface of AZ31 Mg alloy during SP. Higher hardness, increased surface energy and decreased corrosion resistance were observed for the shot-peened surface due to nanostructured grains resulted from SP. From the immersion studies in a simulated physiological solution carried out for 3 days, higher level of biomineralization was observed for the shot peened AZ31 compared with the base alloy that dominated the adverse effect of iron diffusion in resisting the biocorrosion. The results suggest that the nano-structuring of AZ31 Mg alloy surface helps to enhance the biomineralization to control the degradation. However, the selection of processing medium is crucial to eliminate the effect of chemical composition change during the process in tailoring the corrosion behaviour of AZ31 Mg alloy for biomedical implant applications.

The ability of different compositions of calcium silicate and epoxy sealers to withstand gutta percha removal via in vitro pull-out testing

Objectiveexamination of the influence of chemical composition changes on the ability of sealers to withstand a pull-out test.Materials and methodsFifty distal or palatal canals of extracted teeth were prepared by Dc Taper files. The teeth were divided into five groups: AH Plus, BJM RCS, Total Fill BC,AH Plus Bioceramic and a group with Gutta Percha with no sealer added. Ten days after obturation, each cone was subjected to the “pull-out test” with the Shimadzo Universal Testing Machine until it was torn or removed from the canal. A force to Stroke graph was generated and the maximum vertex of this graph was recorded. The number of times the cone was torn or removed was recorded.ResultsThe amount of force needed to remove or rupture the cone was significantly higher in all sealer groups compared to the AH Plus Bioceramic group. The force needed for the AH Plus group was double that needed for the AH Plus Bioceramic group 4 (1.87 ± 0.53 N vs 0.93 ± 0.48 N, respectively, P < 0.001). All of the cones (n = 10) in the AH Plus Bio Ceramic Sealer group were removed in their entirety (P = 0.01 compared to each of the other groups).ConclusionsThe addition of macromolecules to epoxy sealer does not change the material’s ability to withstand the pull-out test. Decreasing the amount of tri- and di-calcium silicate compounds combined with increasing amounts of zirconium oxide in a Bioceramic sealer significantly decreased the material’s ability to withstand the pull-out test.

The use of 18S rRNA for identification of the first record of Tadpole Shrimp Lepidurus apus (Linnaeus, 1758) from Jordan

Abstract. Abushattal S, Alnasarat H, Alnaimat SM, Eid E. 2024. The use of 18S rRNA for identification of the first record of Tadpole Shrimp Lepidurus apus (Linnaeus, 1758) from Jordan. Biodiversitas 25: 1223-1229. The tadpole shrimps are living fossils that survive in temporary water pools and are considered benthic organisms that swim and feed on tiny organisms. Two genera of tadpole shrimps exist worldwide: Triops and Lepidurus, which share similar ecological niches and habitats but never coincide. The occurrence of the tadpole shrimp Lepidurus apus in Jordan was confirmed for the first time using the 18S rRNA Gene-Based PCR Assay. The experimental approach encompassed the amplification of biological specimens utilizing a universal amplicon measuring approximately 1,500 base pairs (bp), specifically targeting the 18S ribosomal RNA (rRNA) gene. Subsequently, the acquired sequences underwent scrutiny through BlastN search against the GenBank database for validation and comparative analysis. Genetic analysis was needed to define the species accurately, especially with tadpole shrimp's generally high morphological variability. This species was recorded in a temporary freshwater pool in the desert of Al-Jafr in Ma’an governorate in southern Jordan. The DNA analysis showed a 100% identical sequence of the 18S rRNA gene with Lepidurus apus sequences. This record is important due to the ecological role of the tadpole shrimps as filter feeders, consuming algae, bacteria, and other small particles of organic matter, and as a food source for various fish, birds, and other aquatic animals. In addition, it will pave the way for future research to identify its economic importance, such as its role in mosquito control and its potential role in aquaculture. Finally, tadpole shrimp are sensitive to environmental changes and could be used to indicate climatic changes and habitat degradation. This is mainly due to their sensitivity to changes in water quality, including temperature, pH, and chemical composition, and their niche requirements for survival and reproduction. In addition, monitoring tadpole shrimp distribution and comparing it with historical records can reveal patterns of climate-induced range shifts.

Salicylic and tartaric ions co-doped polypyrrole to enhance the corrosion protection of polypyrrole/zinc bilayer coating on ZK60 magnesium alloy in Hank's solution

To enhance the corrosion protection of the polypyrrole/zinc (PPy/Zn) bilayer coating on biodegradable ZK60 magnesium alloy in Hank's solution at 37 °C, sodium salicylate (NaSA) in different concentrations (CNaSA, 0.5–4.0 mM) is selected as a co-doping reagent of tartrate anions (TA−), and an electropolymerization method that combines potentiostatic and galvanostatic synthesis is developed to prepare PPy(TA + SA)/Zn bilayer coatings. The co-doping of SA− suppresses the growth of PPy and notably increases its synthesis potential (Epoly) with increasing CNaSA. The co-doped PPy(TA + SA) films have a surface morphology and thickness similar to the PPy(TA) film. However, their chemical composition, structure, and adhesion strength change notably due to their varying growth conditions. In the long-term immersion test of PPy(TA + SA)/Zn/ZK60 samples, the PPy(TA + SA)/Zn coatings exhibit high stability, and the coating prepared with CNaSA = 1.0 mM has the most prolonged protection time (54 ± 1.5 d). As CNaSA increases, the co-doped PPy(TA + SA) film becomes heavily over-oxidized to produce more defects on PPy chains due to the high Epoly, ultimately decreasing the protection time to 40 ± 1.0 d. The corresponding mechanism involved is thoroughly discussed.