Scanning Electron Microscopy Methods Research Articles

One pot synthesis of amino silane grafted cerium phosphate (AS@CePO4) as an effective anticorrosion nanopigment for epoxy coating

This work proposed a facile method to synthesize an effective anticorrosion nanopigment based on amino silane grafted cerium phosphate for epoxy coated steel system. CePO4 nanoparticles were synthesized from Ce(NO3)3 and Na3PO4 precursors, then surface-grafted with a coupling agent N-2-(aminoethyl)-3-aminopropyl trimethoxysilane (denoted as AS) via a one-pot reaction to obtain the AS@CePO4 nanopigment. The effectiveness of this nanopigment on corrosion protection, dry/wet adhesion strength, and cathodic disbondment resistance was thoroughly evaluated on an epoxy-coated steel system. The composition and morphology of pigments as well as epoxy containing pigments were characterized by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) methods. The adhesion strength, cathodic disbondment resistance and corrosion protection performance characteristics of the coatings were evaluated by pull-off test, cathodic disbondment test, electrochemical and salt spray tests, respectively. The synergic effect from stronger bonding of AS coupling agent and excellent inhibitory ability of CePO4 led to strengthened adhesion strength, better corrosion protection performance, and higher cathodic disbondment resistance of epoxy coated steel system.

Assessment of Some Characteristics of a Novel Photocatalyst Based on Hydrotalcite Mg‐Al‐Ag, Titanium Dioxide and Magnetic Iron Nanoparticles

AbstractThe utilization of metals and metal oxides as photocatalysts is a common method for treating dye contamination. Titanium dioxide nanoparticles (TNPs) are well known for their effectiveness as a photocatalyst in ultraviolet regions, while the inclusion of silver nanoparticles (AgNPs) can improve the photocatalytic properties of the nanocomposite materials in visible light. However, the TNPs and AgNPs are difficult to collect for reuse in water treatment due to their limited dispersion. Henceforth, this work recommended a novel photocatalyst based on hydrotalcite Mg−Al, magnetic Fe3O4 nanoparticles (FNPs), AgNPs, and TNPs prepared using the co‐precipitation method. Additionally, organic silane was first time used as a coupling agent to combine the components together. Consequently, the obtained products were applied for the degradation of methylene blue (MB) under natural sunlight. The characteristics of the synthesized nanocomposites were determined using infrared spectroscopy, vibrating‐sample magnetometer, X‐ray diffraction, dynamic light scattering, and scanning electron microscopy methods. The degradability of MB under sunlight was investigated using ultraviolet‐visible method. Moreover, the antibacterial activity and cytotoxicity of these nanocomposites has been tested and discussed.

Rapidly solidified Al-Cu-Co quasicrystalline alloy: microstructure and catalytic properties

This study presents the characterisation and evaluation of the catalytic potential of an alloy with a composition referring to the quasicrystal from the Al-Cu-Co system. The material was synthesised through a melt-spinning process, providing rapid solidification conditions and a favourable material form of thin ribbons. Microstructural and chemical analyses were performed using scanning electron microscopy, X-ray diffraction and transmission electron microscopy methods. The obtained results confirmed the presence of a major phase which was a decagonal quasicrystal in the form of globular grains and additional crystalline phases occurring along the grain boundaries. The catalytic potential of the materials was explored using phenylacetylene hydrogenation. The catalyst, obtained by pulverising the ribbons, demonstrated catalytic activity with over 40% phenylacetylene conversion and selectivity exceeding 60% for styrene production under mild reaction conditions. The recovered catalyst displayed a stable phase composition, as confirmed by X-ray diffraction, and unchanged morphology, indicating the possibility of catalyst reuse for subsequent reaction cycles. The presented results provide insight into the experimental verification of the catalytic properties of the developed environmentally friendly catalysts.

Enhancing biocompatibility and osseointegration of medical implants using ti based nanocomposite coatings

The surface of the replacement medical implant can be coated, which is one of the most basic and effective ways to develop and strengthen bones and increase their compatibility for the human body to solve problems with bone defects, such as the problem of releasing ions from some elements of the body Medical alloy implants are one of the major drawbacks in bone fracture surgery, and biocompatible implants are new ways to ensure that these implants work well. These implants play a major role in accelerating osseointegration processes, but at the same time they suffer from the problem of releasing niobium and zirconium ions, which may cause serious diseases to human health. To stop these toxic ions from releasing, a bioceramic nanolayer coating was put on the alloy's surface. This made it more biocompatible and stopped the toxic ions from escaping. Among several types of coatings, the best nanocomposite coating was selected. Three criteria and levels were used: voltage, time, and cocentartion. A Takeuchi statistical program was used to collect data on all the tests (thickness, adhesion, contact angle, and roughness) in order to find the best coated sample. The study then used atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM) methods.

Electrochemical Deposition and Properties of Ni Coatings with Nitrogen-Modified Graphene Oxide

In this study, a method for producing nitrogen-modified graphene oxide (NMGO) using hydrothermal synthesis in the presence of triethanolamine is presented. The composition and structure of NMGO are characterized using X-ray phase analysis (XPA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and Raman spectroscopy. Ni-based metal matrix coatings (MMCs) modified with NMGO were obtained from a sulfate-chloride electrolyte in the galvanostatic mode. The process of electrochemical deposition of these coatings was studied using chronovoltammetry. The microstructure of Ni–NMGO MMCs was studied using the XPA and SEM methods. It has been established that the addition of NMGO particles into the Ni matrix results in an increase in the microhardness of the resulting coatings by an average of 1.30 times. This effect is a consequence of the refinement of crystallites and high mechanical properties of NMGO phase. The corrosion-electrochemical behavior of studied electrochemical deposits in 0.5 M sulfuric acid was analyzed. It has been shown that the corrosion rate of Ni–NMGO MMCs in a 3.5% sodium chloride environment decreases by approximately 1.50–1.70 times as compared to unmodified Ni coatings. This is due to NMGO particles that act as a barrier preventing the propagation of the corrosion and form corrosive galvanic microelements with Ni, promoting anodic polarization.

WO3/ZnWO4 microcomposites with potential application in photocatalysis

The paper presents the results of a comprehensive study of the structural, optical and strength features, changes in the morphology of grains of (1-x)WO3 – xZnO ceramics depending on the concentration of the initial components when they vary. Using the X-ray diffraction method, it was found that mechanochemical grinding of samples of (1-x)WO3 – xZnO ceramics, regardless of the concentration of the components, does not lead to the initiation of phase transformation processes associated with the formation of the monoclinic ZnWO4 phase, the formation of which is observed during thermal annealing of samples at a temperature of 1000 °C. Based on data obtained using scanning electron microscopy and X-ray diffraction methods, the dynamics of phase transformations in ceramics of the type WO3/ZnWO4 → ZnWO4 → ZnO/ZnWO4 was established. It was found that with a given ratio of WO3: ZnO components equal to 0.7 : 0.3, under selected conditions of mechanochemical grinding and an annealing temperature of 1000 °C, highly ordered single-phase ZnWO4 ceramics with a wolframite structure can be obtained. Analysis of the optical characteristics and changes in the band gap depending on the ratio of the components showed a direct dependence of changes in the band gap on the phase composition of the ceramics. An assessment of the strength characteristics made it possible to establish that the formation of two-phase WO3/ZnWO4 ceramics leads to strengthening of the surface layer, while for two-phase ZnO/ZnWO4 ceramics a decrease in hardness is observed, the decrease of which directly correlates with changes in the content of the ZnO phase in the composition of the ceramics.

Specific surface area and microstructure of the surface of soil solid substrates of different genesis

The sorption characteristics of sand, peat, the arable layer of Moscow urbanozem and a mixture of these substrates were studied in conjunction with the surface topography of their solid phase, studied by scanning electron microscopy (SEM). The arable layer has the greatest ability to absorb nitrogen, and the peat substrate showed very low values of the sorbed gas. A different picture of the mutual arrangement of substrate sorption isotherms is observed when water vapour is used as a sorbing gas. Peat is distinguished by high values of sorbed moisture in the entire studied range of relative humidity. This leads to differences in the ranking of substrates by specific surface area in descending order of its values. So, the specific surface area by water sorption in the series: peat / arable layer / mixture / sand was: 420 / 72 / 45 / 4 m2/g, respectively. The given surface was ranked according to nitrogen sorption in a different sequence: 8.31 / 2.41 / 1.45 / 0.55 for the series: arable layer, mixture, peat and sand, respectively. The analysis of microstructural characteristics by the SEM method at various magnifications revealed the most developed, rough surface in the arable layer. It turned out to be geometrically the most diverse, even at magnification of ×20 000. The variety and heterogeneity of the relief of the interface of the phases leads to the appearance of hysteresis of the sorption/desorption curves. Its severity in the range of nitrogen vapor concentration in which hysteresis is detected, and in the maximum width of the hysteresis loop, also turned out to be the most significant in the arable layer. The very low nitrogen specific surface of peat, which is close to a sandy substrate, is associated with the presence of organic films draping and leveling the surface of peat particles, which was revealed by analyzing images obtained by scanning electron microscopy. The sorption of water showed their high hydrophilicity, which led to high values of substrate humidity in the entire studied range of relative humidity.

“Exploring the Inhibitory Potential of Acetoxime-Zinc Chloride Adduct in Saline Environments for Mild Steel Corrosion Protection”

ABSTRACT In this work, acetoxime, zinc chloride and acetoxime adduct of zinc chloride, [ZnCl2.2{HON=C(CH3)2}] (ZA) were investigated as corrosion inhibitor's in 3.5%NaCl solution on mild steel. The electrochemical analysis was carried out using polarization measurements and electrochemical impedance technique and surface analysis was done by Scanning electron microscope coupled with Energy-dispersive X-ray spectroscopy. Using surface analysis and electrochemical data it was concluded that an inhibition synergy was developed when ZA was taken instead of acetoxime or zinc chloride alone in solution phase. Scanning electron microscope methods were used to examine the samples surface in the presence of inhibited solutions. The efficiency of inhibition increases with the increasing concentration and attained the values of 97.18% for the 3mM concentration of ZA.

Cathodoluminescence differentiates sedimentary organic matter types

High-resolution scanning electron microscopy (SEM) visualization of sedimentary organic matter is widely utilized in the geosciences for evaluating microscale rock properties relevant to depositional environment, diagenesis, and the processes of fluid generation, transport, and storage. However, despite thousands of studies which have incorporated SEM methods, the inability of SEM to differentiate sedimentary organic matter types has hampered the pace of scientific advancement. In this study, we show that SEM-cathodoluminescence (CL) properties can be used to identify and characterize sedimentary organic matter at low thermal maturity conditions. Eleven varied mudstone samples with a broad array of sedimentary organic matter types, ranging from the Paleoproterozoic to Eocene in age, were investigated. Sedimentary organic matter fluorescence intensity and CL intensity showed an almost one-to-one correspondence, with certain exceptions in three samples potentially related to radiolytic alteration. Therefore, because CL emission can be used as a proxy for fluorescence emission from sedimentary organic matter, CL emission during SEM visualization can be used to differentiate fluorescent from non-fluorescent sedimentary organic matter. This result will allow CL to be used as a visual means to quickly differentiate sedimentary organic matter types without employing correlative optical microscopy and could be widely and rapidly adapted for SEM-based studies in the geosciences.

Glycyrrhizae radix et rhizoma processing ameliorates adverse reactions of polygalae radix in zebra fish and rabbit models

Ethnopharmacological relevancePolygala tenuifilia Willd (Polygalaceae), a traditional Chinese medicine, has been used for a long time to treat various illnesses with serious adverse reactions. Glycyrrhizae radix et rhizoma processing is generally used to reduce the adverse reactions. Aim of the studyThe aim of this study was to validate the irritation caused by raw Polygalaceae (RPA), to investigate whether processed Polygalaceae (PGA) was less irritating, and to screen and validate irritant properties of virgaureagenin G (polygala acid, PA), 3,6′-disinapoylsucrose (DSS), Tenuifolia (TEN) and polygalaxanthone III (POL), which had pharmacologically active in Polygalaceae. Zebrafish model, Draize test and High-Performance Liquid Chromatography (HPLC) were utilized to achieve the aim. Materials and methodsScanning Electron Microscopy (SEM) and optical microscope were used to determine the presence of calcium oxalate needle crystal in RPA and PGA. Zebrafish egg spinning changes and zebrafish embryo behavior were used for irritation validation, irritation comparison and irritant screening. For additional evidence, the Draize test, HE staining of rabbit eyes and ELISA kit were used. Finally, changes in the composition of RPA and PGA were investigated using HPLC. ResultsSEM and optical microscopy revealed no calcium oxalate needle crystals in Polygalaceae. RPA, PGA, PA and DSS were able to accelerate the spinning of zebrafish eggs and the movement of embryos, while TEN and POL were not. RPA, PGA, DSS and PA may cause rabbit eyes to become hyperemic and swollen, resulting in damage to the iris, cornea and conjunctiva and increased levels of interleukin-6 (IL-6) and interleukin-10 (IL-10). Comparatively, the effects caused by PGA were less severe than those caused by RPA. In addition, compared to RPA, PGA had lower levels of DSS and PA. ConclusionsRPA, PGA, DSS, and PA were irritating. However, processing and curing could reduce the irritation by reducing the levels of DSS and PA. DSS and PA could be two potential irritants of Polygalaceae.

Li3V2(PO4)3 Cathode Material: Synthesis Method, High Lithium Diffusion Coefficient and Magnetic Inhomogeneity.

Li3V2(PO4)3 cathodes for Li-ion batteries (LIBs) were synthesized using a hydrothermal method with the subsequent annealing in an argon atmosphere to achieve optimal properties. The X-ray diffraction analysis confirmed the material's single-phase nature, while the scanning electron microscopy revealed a granular structure, indicating a uniform particle size distribution, beneficial for electrochemical performance. Magnetometry and electron spin resonance studies were conducted to investigate the magnetic properties, confirming the presence of the relatively low concentration and highly uniform distribution of tetravalent vanadium ions (V4+), which indicated low lithium deficiency values in the original structure and a high degree of magnetic homogeneity in the sample, an essential factor for consistent electrochemical behavior. For this pure phase Li3V2(PO4)3 sample, devoid of any impurities such as carbon or salts, extensive electrochemical property testing was performed. These tests resulted in the experimental discovery of a remarkably high lithium diffusion coefficient D = 1.07 × 10-10 cm2/s, indicating excellent ionic conductivity, and demonstrated impressive stability of the material with sustained performance over 1000 charge-discharge cycles. Additionally, relithiated Li3V2(PO4)3 (after multiple electrochemical cycling) samples were investigated using scanning electron microscopy, magnetometry and electron spin resonance methods to determine the extent of degradation. The combination of high lithium diffusion coefficients, a low degradation rate and remarkable cycling stability positions this Li3V2(PO4)3 material as a promising candidate for advanced energy storage applications.

High‐temperature resistant copolymer oil well cement retarder: Synthesis, assessment of performance, and mechanism of retardation

AbstractThis work used aqueous solution free radical polymerization to create polymers of 2‐acrylamide‐2‐methylpropane sulfonic acid, itaconic acid, and allyl polyoxyethylene ether as a high‐temperature resistant retarder (APMS/IA/APEG, from now on referred to as AIA). Gel permeation chromatography, fourier transform infrared (FTIR), proton nuclear magnetic resonance (1HNMR), and thermo‐gravimetric analysis (TG) were used to characterize their molecular structure and characteristics. Tests were conducted on the thickening time, rheological characteristics, and compressive strength of AIA in cement slurries. The cement slurry thickened for 276 min at 180°C during the test, and the cement stone's 24‐h compressive strength was consistently more than 20 MPa. The hydration products were analyzed using x‐ray diffractometer and scanning electron microscopy methods, which were then coupled with molecular dynamics simulations to elucidate the AIA retarding mechanism. When AIA is added to a cement slurry, it forms a chelate structure with Ca2+ and a strong adsorption layer on the surfaces of the cement particles. This stops the cement from hydrating. The AIA side chain, APEG, can wrap the active group in AIA at low temperatures. AIA exposes more adsorption groups because of the APEG chains stretching at higher temperatures. AIA can, therefore, be used for deep well operations at high temperatures.

Analysing suspected linear indications in narrow-gap welding of nuclear power plants via radiographic inspection

ABSTRACT In nuclear power plants, ensuring the integrity of main coolant line welding is vital. Radiographic testing often shows linear indications in these welds, posing challenges for quality assessment and requiring expensive reworking. To investigate the mechanism of the suspected linear indications observed in radiographic inspections of narrow-gap welding at nuclear power plants, the microstructure, microhardness, and porosity of welds showing such indications were investigated in this study using scanning electron microscopy and atomic probing methods, among others. The microvoid distribution in narrow-gap welds was characterised by porosity measurement. The results showed that the microstructure of the weld consists of an austenite matrix and δ-ferrite, with the latter distributed almost uniformly during welding. The average δ-ferrite content and microhardness were approximately 6.6% and 186 HV0.49N, respectively. The porosity of the welding zone with a suspected linear indication was approximately 0.06%, higher than the 0.03% observed in the zones without such indications. This difference is likely responsible for the linear indications detected in radiographic inspections. However, the results demonstrated that this difference does not affect the welding microhardness. The novelty of this study lies in explaining the role of porosity in causing suspected linear indications in narrow-gap welding in nuclear power plants.

Biogenic Synthesis and Characterisation of Flueggea leucopyrus Willd Leaf Mediated Copper Nanoparticles for Antibacterial, Antioxidant, and Antidiabetic Activities

IntroductionThe chemical synthesis of metal Nanoparticles could be changed into green synthesis if solvents, stabilising agents, and reducing agents are environmentally friendly. Our aims were to synthesise and characterise bioconjugated copper nanoparticles (CuNPs) and evaluate their antibacterial, antioxidant, and antidiabetic activities. MethodsThis study was made to synthesise CuNPs using Flueggea leucopyrus Willd leaf extract. The produced CuNPs were characterised using UV-visible, Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), TEM, EDX, and Zeta-potential analytical methods. The antibacterial, antioxidant, and antidiabetic properties of CuNPs were screened through disc diffusion methods, 2,2-diphenyl-1-picrylhydrazyl radical quenching, and alpha-amylase inhibition assay, respectively. ResultsThe CuNPs are poly-dispersed, spherical, crystalline, and stable with an average particle size of 20 nm. These nanoparticles show antibacterial activity and exhibit the same inhibition zone against S aureus and P aruginosa (13 mm), a strong zone for E faecalis, and no inhibition zone for E coli bacteria. The CuNPs demonstrated dose-dependent sequencing and inhibition activities with an IC50 value of 100.06 ppm and 435.68 ppm, respectively. ConclusionsThis study shows that these poly-disperse CuNPs could act as a bacterial resistance agent, antioxidant, and antidiabetic drug. It concluded that CuNPs made from medicinal plant leaf extract have good inhibitory potential against alpha-amylase, one of the main pharmacological targets for treating type 2 diabetes.

Synthesis of Tin Doped Copper Oxide Nanocomposites for Electrochemical Sensor Application

Abstract Poly (Tin-doped copper oxide nanocomposites modified glassy carbon electrode) (Poly (Sn-doped CuO nanocomposite)-MGCE) made sensors were confirmed by electrochemical finding of norepinephrine (NE). The Sn-doped CuO nanocomposites were made by precipitation technique. This nanocomposite was described through scanning electron microscope and X-ray diffraction methods. To find the doped properties of the Poly (Sn-doped CuO nanocomposite)-MGCE were studied by cyclic voltammetry studies. The above studies prove that the altered electrodes have wide electroactive external area, and the reduction and oxidation peak appeared at pH 7.4 supportive electrolyte concentration 0.2 M phosphate buffer solution. Poly(Sn-doped CuO nanocomposite)-MGCE as limit of detection was low value for NE was found to be 2.22 µM and the limit of quantification values for NE was appeared as 7.41 µM, wide linear range, high sensitivity (20 to 350 µM), functional to the injection mockup analysis and the attained outcomes are acceptable, excellent reproducibility displays excessive potential in practical applications.

The Regularities of Metal Transfer by a Nickel-Based Superalloy Tool during Friction Stir Processing of a Titanium Alloy Produced by Wire-Feed Electron Beam Additive Manufacturing

In this work, the interaction of an additively produced Ti-4Al-3V titanium alloy with a nickel superalloy tool and the features of the stir zone formation during friction stir processing have been studied. The stop-action technique was used to produce the samples to be studied using optical and scanning electron microscopy methods, as well as microhardness measurements. As a result, it was revealed that the tool, when moving, forms a pre-deformed area in front of it, which is characterized by a fine-grained structure. The presence of an interface layer between the workpiece material and primary fragmentation by the tool was revealed. It was demonstrated that the transfer of titanium alloy material occurs periodically following the ratio of feeding speed to tool rotation rate. Metal flow around the tool can occur in both laminar and vortex modes, as indicated by the tool material stirred into the transfer layer and used as a marker.

Significantly Enhanced Balance of Dielectric Properties of Polyvinylidene Difluoride Three-Phase Composites by Silver Deposited on K2Ni0.93Ti7.07O16 Hollandite Nanoparticles.

Three-phase polymer composites are promising materials for creating electronic device components. The qualitative and quantitative composition of such composites has a significant effect on their functional, in particular dielectric properties. In this study, ceramic filler K2Ni0.93Ti7.07O16 (KNTO) with Ag coating as conductive additive (0.5, 1.0, 2.5 wt.%) was introduced into the polyvinylidene difluoride (PVDF) polymer matrix in amounts of 7.5, 15, 22.5, and 30 vol.%. to optimize the dielectric constant and dielectric loss tangent. The filler was characterized by X-ray phase analysis, Fourier-transform infrared spectroscopy and Scanning electron microscopy methods. The dielectric constant, dielectric loss tangent, and conductivity of three-phase composites KNTO@Ag-PVDF were studied in comparison with two-phase composites KNTO-PVDF in the frequency range from 102 Hz to 106 Hz. The dielectric constant values of composites containing 7.5, 15, 22.5, and 30 vol.% filler were 12, 13, 17.4, 19.2 for pure KNTO and 13, 19, 25, 31 for KNTO@Ag filler (2.5 wt.%) at frequency 10 kHz. The dielectric loss tangent ranged from 0.111 to 0.340 at a filler content of 7.5 to 30 vol.%. A significantly enhanced balance of dielectric properties of PVDF-based composites was found with K2Ni0.93Ti7.07O16 as ceramic filler for 1 wt.% of silver. Composites KNTO@Ag(1 wt.%)-PVDF can be applied as dielectrics for passive elements of flexible electronics.

Preliminary Magnetic Mineralogical Studies of Lake Beloe Sediments (Southern Siberia, Russia)

This article overviews the results of a preliminary magnetic and mineralogical study of the bottom sediments of Lake Beloe (Southern Siberia, Russia). The magnetic and mineralogical properties of the sediments were examined. Their variations were correlated with geological factors. A comprehensive magnetic survey was performed: magnetic susceptibility of samples extracted from three sediment cores was measured; normal remanent magnetization in a continuously increasing external magnetic field of up to 1.5 T was calculated; differential thermomagnetic analysis was carried out based on induced magnetization and scanning electron microscopy (SEM) for certain samples. The magnetic component was divided into three subcomponents based on the normal magnetization curves: ferromagnetic, dia-/paramagnetic, and superparamagnetic. The contribution of each subcomponent to the total magnetization was determined. It was found that the magnetic susceptibility values correlate well across all the studied cores, thus making it possible to compare them. Magnetite and pyrite turned out to be the magnetic minerals distributed throughout almost the entire section. In the Day–Dunlop plot, the studied samples are represented by single-domain (SD) and pseudo–single-domain (PSD) grains. The magnetic components vary consistently along the section, suggesting that the depositional environment underwent substantial changes. Particles similar in composition and morphology to cosmogenic and volcanic spherules were discovered using the SEM method. Based on the obtained results, the boundary between the Pleistocene and Holocene deposits was defined.

УСОВЕРШЕНСТВОВАНИЕ ЗОНАЛЬНОЙ ДИАТОМОВОЙ ШКАЛЫ НЕОГЕНА ПРИМОРЬЯ (РОССИЯ)

Comprehensive study of diatoms from some Neogene stratotype sections of southern Primorye (Sineutesovskaya and Novokachalinskaya formations, Shufansky horizon) using light and scanning electron microscopy methods allowed adjustments to be made to the Zonal Diatom Scale of the Neogene in Primorye. Studies have shown the absence of some zone index species in the sediments: Alveolophora bifaria, A. jouseana, A. areolata. As a result, the corresponding subdivisions of the Scale received new names: Alveolophora hachiyaensis-Aulacoseira elliptica zone, Alveolophora khankaica zone, Alveolophora khursevichiae zone. The position of the Shufansky horizon zones has changed: the Aulacoseira praeislandica zone now corresponds to the Early Pliocene, and the Alveolophora tscheremissinovae zone to the Upper Pliocene. According to the International Stratigraphic Chart of the Cenozoic, the age of the upper boundary of the Alveolophora tscheremissinovae zone was revised to 2.58 Ma ago.

Embryonic development of the scorpion mud turtle (Kinosternon scorpioides) bred in captivity.

The developmental biology of Kinosternon scorpioides is described, based on the phenotype. This species is important for the flora because they are excellent seed disseminators. In addition, basic embryological information is not yet fully clarified, and this research provides unprecedented information on the chelonian embryology of the Amazonian fauna. The present study aims to identify the embryology of K. scorpioides in captivity during different periods. Females were monitored throughout the reproductive cycle, by video monitoring, to identify nests and the presence of newly laid eggs. At regular weekly intervals, embryo samples were collected fixed in a 4% paraformol solution and preserved in 70% alcohol. For the embryonic characterization, we used a stereomicroscope and the scanning electron microscopy method. We describe 15 embryonic stages for a 15-week (105-day) incubation process. Only at 42 days (6th week) was the morphological characterization of a chelonian observed and at the 12th week (Stage XII), the phenotypic characterization of the species K. scorpioides. In view of the evidence, we found that these phases are similar to the other turtles, with structural variations in the appearance and disappearance of structures due to the specific characteristics of the species.