Hasil untuk "Microscopy"

Società Italiana di Biologia Sperimentale

Seasonal reproduction is a widespread adaptive strategy in mammals, ensuring that offspring are born during periods favorable for survival and growth. Sheep exhibit marked annual cycles of reproductive activity: females alternate between phases of ovarian activity and ovulation (the breeding season) and phases of ovarian quiescence and anovulation (anestrus) (Karsch et al., 1980). In Sarda sheep, the breeding season typically begins in early summer (May–June) and ends in the following spring (March–April). This seasonality is regulated by photoperiod, with long days suppressing and short days stimulating reproductive activity (Mara et al., 2013). Mammalian oocytes contain species specific stores of lipids, which play essential roles during maturation and early embryonic development. Ovine oocytes, similar to bovine and porcine ones, contain lipid droplets (LDs) that serve as energy reserves. In mature oocytes, LDs tend to be more uniformly distributed, reflecting metabolic activity and developmental competence. Lipid content and metabolism—rather than total lipid quantity alone—are key indicators of oocyte quality and are associated with successful maturation and embryo development (Reader et al., 2017). This study investigated seasonal effects on oocyte morphology and LDs organization in Sarda sheep using phase-contrast and confocal microscopy, focusing on LDs as markers of oocyte quality. Oocytes were collected from ovaries of adult ewes at slaughter during winter (January–March; W) and spring/summer (May–July). Summer samples were further classified as oocytes from non pregnant (SNG) and pregnant (SG) ewes. Morphology was first assessed by phase contrast microscopy. LDs were then visualized by confocal laser scanning microscopy using BODIPY 493/503, with DAPI nuclear counterstaining. Quantitative and morphometric analyses of LDs—including numerical density and fluorescence intensity—were performed using ImageJ. Phase contrast microscopy revealed well rounded oocytes in the W and SNG groups, whereas SG oocytes displayed irregular shapes with spikes in the perivitelline space. Confocal imaging showed distinct patterns of lipid distribution: W oocytes contained numerous small, homogeneous, highly fluorescent LDs; SNG oocytes exhibited larger, more dispersed, and less fluorescent LDs; SG oocytes displayed even larger LDs, some appearing partially depleted. The lighter cytoplasm observed in W oocytes suggests differences in lipid composition compared with the darker cytoplasm of SNG and SG oocytes. In conclusion, both oocyte morphology and lipid organization vary seasonally in Sarda sheep. The presence of cytoplasmic spikes and altered LDs patterns in SG oocytes may indicate delayed cytoplasmic maturation and metabolic imbalance. Confocal lipid imaging thus represents a valuable tool for assessing oocyte quality. Future ultrastructural studies may further elucidate how environmental factors, including climate change, influence oocyte competence.

Mohammed Ghazwani, Umme Hani

Abstract This study investigates the characteristics of cobalt ferrite nanofluids, focusing on their structural, thermal, electrical conductivity, and viscosity properties. The motivation behind this research lies in the potential applications of nanofluids in advanced thermal management systems due to their enhanced properties. Characterization techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometer measurements, were employed to analyze the nanofluids. X-ray diffraction results indicate that cobalt ferrite nanoparticles crystallize in a spinel structure with Fd-3 m symmetry. Dynamic light scattering and transmission electron microscopy confirm that the nanoparticles have dimensions of approximately 25 nm and exhibit specific ferromagnetic properties at temperatures below 435 K, as demonstrated by the magnetization curve. Thermal conductivity measurements were conducted across various volume fractions, ranging from 1 to 5%, and under magnetic fields of 0.05 and 0.1 T at temperatures of 300.15, 313.15, and 323.15 K. The findings reveal a significant dependence of thermal conductivity on both magnetic field and temperature. For instance, at 300.15 K, increasing the volume fraction from 1 to 5% results in a rise in thermal conductivity from 0.59 to 0.88 W/m.K, representing a 49% increase. Additionally, applying a magnetic field of approximately 0.1 T increases the thermal conductivity coefficient for a 1% volume fraction from 0.59 to 0.72 W/m.K, leading to a growth of about 22%. The electrical conductivity coefficient also varies with different volume fractions and magnetic field intensities, with a maximum increase of around 11% observed at a 4% volume fraction under a 0.1 T magnetic field. In terms of viscosity, no significant changes were noted for volume fractions below 1.5%, while a slight decrease in dynamic viscosity was observed for higher fractions with increasing magnetic field strength. These results demonstrate that the application of a magnetic field enhances the flow properties of the nanofluid, highlighting its potential for improved thermal management applications.

Hyun Tae Kim

Abstract This study investigated the anatomy and histology of the olfactory organ of the Korean amur goby Rhinogobius brunneus from Jeonjucheon stream. This species lives in shallow, stagnant, and intermittently low-oxygenated streams, reservoirs, and ponds affected by seasonal rainfall. Anatomically, its olfactory organ consisted of a short tubular anterior nostril, a posterior nostril, a single longitudinal lamella, and two accessory nasal sacs (ethmoidal and lacrymal sacs). Its single lamella structure resembles other gobiid fishes with a simplified olfactory surface. Histologically, the sensory epithelium comprised olfactory receptor neurons, supporting cells, and basal cells, while the non-sensory epithelium contained stratified epithelial cells, basal cells, and mucous cells. In particular, the mucous cells stained intensely red with Hematoxylin and eosin and Masson’s trichrome, indicating proteinaceous granular mucins rich in glycoproteins; such secretions likely protect the epithelium against particles, toxins, and low-oxygenated freshwater. Overall, the goby’s olfactory organ exhibits traits uniquely adapted to stagnant and hypoxic conditions.

Miryana Raykovska, Hristina Tankova, Evgeni Koytchev et al.

This case report aims to present micro CT and SEM analysis of type II dens invaginatus extracted for orthodontic reasons three years after the eruption. An industrial micro CT was used to double scan a freshly extracted left lateral incisor from the upper jaw with a peg shape and type II invagination, according to Ohlers. The first scan captured the entire tooth with a resolution of twelve micrometers, while the second scan focused on the coronal part of the tooth with a magnification of seven micrometers. This allowed for a detailed view of the overall anatomy and a reliable representation of the tooth's structure. After the scanning procedure, the tooth was sectioned, and SEM-EDS was performed on the invagination to obtain further details. Segmented image analysis provides a new detailed overview of the structural and morphological characteristics that can be observed in this type of malformation. This anatomical presentation, and SEM analysis can bring new helpful insights for practitioners and students to navigate their treatment strategies.

Debora Maria Conti, Claudia Urru, Giovanna Bruni et al.

The NASICON-structured Na₃MnZr(PO₄)₃ compound is a promising high-voltage cathode material for sodium-ion batteries (SIBs). In this study, an easy and scalable electrospinning approach was used to synthesize self-standing cathodes based on Na₃MnZr(PO₄)₃ loaded into carbon nanofibers (CNFs). Different strategies were applied to load the active material. All the employed characterization techniques (X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), thermal gravimetric analysis (TGA), and Raman spectroscopy) confirmed the successful loading. Compared to an appositely prepared tape-cast electrode, Na₃MnZr(PO₄)₃/CNF self-standing cathodes demonstrated an enhanced specific capacity, especially at high C-rates, thanks to the porous conducive carbon nanofiber matrix. Among the strategies applied to load Na₃MnZr(PO₄)₃ into the CNFs, the electrospinning (vertical setting) of the polymeric solution containing pre-synthesized Na₃MnZr(PO₄)₃ powders resulted effective in obtaining the quantitative loading of the active material and a homogeneous distribution through the sheet thickness. Notably, Na₃MnZr(PO₄)₃ aggregates connected to the CNFs, covered their surface, and were also embedded, as demonstrated by TEM and EDS. Compared to the self-standing cathodes prepared with the horizontal setting or dip–drop coating methods, the vertical binder-free electrode exhibited the highest capacity values of 78.2, 55.7, 38.8, 22.2, 16.2, 12.8, 10.3, 9.0, and 8.5 mAh/g at C-rates of 0.05C, 0.1C, 0.2C, 0.5C, 1C, 2C, 5C, 10C, and 20C, respectively, with complete capacity retention at the end of the measurements. It also exhibited a good cycling life, compared to its tape-cast counterpart: it displayed higher capacity retention at 0.2C and 1C, and, after cycling 1000 cycles at 1C, it could be further cycled at 5C, 10C, and 20C.

Moshood O. Bolarinwa, Aasif A. Dabbawala, Shamraiz Hussain Talib et al.

Single-atom catalysts (SACs) offer high efficiency and selectivity in chemical reactions but face challenges in converting CO2 to CO via the reverse water gas shift (RWGS) reactions. This study addresses these challenges by anchoring three noble metals (Ir, Pd, and Ru) onto titania (TiO2) and analyzing their performance. Comprehensive characterization techniques, including electron microscopy, confirmed the uniform dispersion of metal atoms on TiO2. Among the catalysts, Ir/TiO2 exhibited the best results, achieving an 84 % CO2 conversion rate and ∼98 % CO selectivity, surpassing Pd/TiO2 and Ru/TiO2, which gained 56 % and 52 % conversion, respectively. In-situ gas transmission electron microscopy revealed the catalytic behavior of Ir/TiO2, showing Ir atom mobility and the formation of ∼1 nm nanoclusters. Density functional theory (DFT) and in-situ diffuse reflectance infrared spectroscopy (DRIFTs) further explained that the atomically dispersed Ir sites in Ir/TiO2 follow a hydrogen-assisted mechanism, with the COOH* intermediate desorbing and dissociating into CO. These findings suggest SACs' potential to facilitate greener chemical processes and reduce greenhouse gas emissions.

Serisha Gangaram, Yougasphree Naidoo, Yaser Hassan Dewir et al.

<i>Barleria albostellata</i> (Acanthaceae) is a shrub located in South Africa and is relatively understudied. However, plants within this genus are well known for their medicinal and ethnopharmacological properties. This study aimed to characterise the phytochemical compounds and antibacterial efficacies of <i>B</i>. <i>albostellata</i>. Phytochemical analysis, fluorescence microscopy and gas chromatography-mass spectrometry (GC-MS) analysis were performed to determine the composition of compounds that may be of medicinal importance. Crude leaf and stem extracts (hexane, chloroform and methanol) were subjected to an antibacterial analysis against several pathogenic microorganisms. The qualitative phytochemical screening of leaf and stem extracts revealed the presence various compounds. Fluorescence microscopy qualitatively assessed the leaf and stem powdered material, which displayed various colours under bright and UV light. GC-MS chromatograms represents 10–108 peaks of various compounds detected in the leaf and stem crude extracts. Major pharmacologically active compounds found in the extracts were alpha-amyrin, flavone, phenol, phytol, phytol acetate, squalene and stigmasterol. Crude extracts positively inhibited Gram-positive and Gram-negative bacteria. Significance was established at <i>p</i> < 0.05 for all concentrations and treatments. These results indicate that the leaves and stems of <i>B. albostellata</i> are rich in bioactive compounds, which could be a potential source of antibacterial agents for treating various diseases linked to the pathogenic bacteria studied. Future discoveries from this plant could advance the use of indigenous traditional medicine and provide novel drug leads.

Katia Cortese, Paul Verkade

Alaa Majeed, Rashed Rasheed

Different iron oxide nanoparticles (Fe₃O₄ and Fe₂O₃) were prepared by the sol-gel method (titration). The prepared nanoparticles were heated at 90 and 400°C. The morphology surface and structures were characterized by Fourier Transform Infra-Red (FT-IR) and Ultraviolet/Visible (Uv/Visible) measurements, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscope (AFM). The enzyme mimetic activities of these nanoparticles (Fe₃O₄ and Fe₂O₃) such as two enzymes (Catalase (CAT), and Peroxidase (Pxase)) were measured. The results showed the iron oxides (Fe₂O₃) heated at 90°C, have the maximum activity (189.99 K.min^-1) as catalase (CAT). While the iron oxides (Fe₃O₄) heated at 90°C, have the maximum activity (3.044 U.min^-1) as peroxidase (Pxase), and there is a decrease in the activity for both nanoparticles when annealed at 400°C. Despite the average grain size decrease in both samples, however, the mimetic activity decrease that is mean the average grain size is not affected in both mimetic activities as catalase and peroxidase.

Muhammad Fauzi, Takaaki Murakami, Hiroyuki Fujimoto et al.

Progressive loss of β-cell mass (BCM) has a pernicious influence on type 2 diabetes mellitus (T2DM); evaluation of BCM has conventionally required an invasive method that provides only cross-sectional data. However, a noninvasive approach to longitudinal assessment of BCM in living subjects using an indium 111–labeled exendin-4 derivative ([Lys12(111In-BnDTPA-Ahx)]exendin-4) (111In-exendin-4) has been developed recently. Imeglimin is a novel antidiabetic agent that is reported to improve glycemic control and glucose-stimulated insulin secretion (GSIS) via augmentation of mitochondrial function. However, the influence of imeglimin on BCM is not fully understood. We have investigated the effects of imeglimin on BCM in vivo in prediabetic db/db mice using a noninvasive 111In-exendin-4 single-photon emission computed tomography/computed tomography (SPECT/CT) technique. During the 5-week study period, imeglimin treatment attenuated the progression of glucose intolerance, and imeglimin-treated mice retained greater BCM than control, which was consistent with the results of 111In-exendin-4 SPECT/CT scans. Furthermore, immunohistochemical analysis revealed reduced β-cell apoptosis in the imeglimin-treated db/db mice, and also lowered release of cytosolic cytochrome c protein in the β cells. Furthermore, electron microscopy observation and membrane potential measurement revealed improved structural integrity and membrane potential of the mitochondria of imeglimin-treated islets, respectively. These results demonstrate attenuation of progression of BCM loss in prediabetic db/db mice partly via inhibition of mitochondria-mediated apoptosis.

Mohamed Zemzem, Ludwig Vinches, Stéphane Hallé

The dispersion and orientation of three different montmorillonite clay nanoparticles embedded in nitrile-based nanocomposites were examined in the current study. Maleic anhydride was grafted onto a nitrile structure for the purpose of enhancing compatibility, and the resulting nanocomposites were investigated. The grafting of maleic anhydride seemed to have a pronounced effect, leading the structure to a near-exfoliation state. Using energy dispersive x-ray spectrometer, the state of distribution of layered silicate clusters in the nanocomposite was assessed, and it was observed that maleic anhydride provided a reduction in the size of agglomerations and enhanced the homogeneity of the system. The intercalation and delamination of the layered silicates over grafting were validated by transmission electron microscopy. Inter-lamellar spacing measurements were found to correlate perfectly with x-ray data. On the other hand, the alignment of the clay nanoparticles was examined by small angle x-ray scattering. A 3D-orientation approach was developed based on the scattering stereographs.

Huiru Wang, Yuanyuan Li, Yunpeng Min et al.

Puerarin (Pue) is the most abundant isoflavonoid in kudzu root. It has been widely used as a therapeutic agent for the treatment of cardiovascular diseases. However, poor-bioavailability of puerarin is the main obstacle to its widespread clinical applications. In this paper, HA-ADH-PS nanomicelles were prepared by chemical modification, noncovalent modification and etc, and characterized by means of FT-IR, ultraviolet (UV) and thermogravimetric analysis (TG). The encapsulation efficiency and drug loading of Pue-loaded HA-ADH-PS nanomicelles were 45.1% and 19.89% by UV, respectively. It could be observed from the transmission electron microscopy (TEM) images that HA-ADH-PS micelles appeared obvious spherical structure in the water. The particle size of HA-ADH-PS nanomicelles and Pue-loaded HA-ADH-PS nanomicelles were about 136.8 nm and 119.5 nm with a PDI of 0.237 and 0.272, respectively. The fluorescence probe method was used to characterize the critical micelle concentration, the critical micelle concentration (CMC) value of the nanomicells was 0.002 g/L and the results met the requirements and ensured the stability of micelles after dilution. DPPH assay suggested that Pue-loaded HA-ADH-PS nanomicelles had an obvious radical scavenging effect in vitro. MTT test showed that Pue-loaded HA-ADH-PS nanomicelles was non-toxic and had good biocompatibility. Thus, Pue-loaded HA-ADH-PS nanomicelles could be used as a potential drug carrier for puerarin.

Pamela Nair Silva-Holguín, Simón Yobanny Reyes-López

Innovative and improved antimicrobial agents by nanotechnology are developed to control and mitigation of resistant microorganisms. Nanoparticles of metals or oxide metals be able to be toxic to bacteria, demonstrating biocidal behaviors at low concentrations. The integration of silver nanoparticles in ceramic matrices has enhanced the antimicrobial performance, resulting in the search for new composites with improved bactericidal properties. The aim of this study was to prepare and characterize hydroxyapatite-silver nanocomposite and evaluate its antimicrobial properties against various Gram-positive and negative bacteria related to drug-resistance infections. Hydroxyapatite nanopowders were produced by sol-gel and silver nanoparticles were synthesized by reduction of Ag + ions with the simple addition of gallic acid. Hydroxyapatite-silver composite (HAp-AgNPs) was prepared by adsorption of AgNPs at several concentrations. The results of UV–visible spectroscopy, dynamic light scattering, and transmission scanning electron microscopy revealed the existence of AgNPs with diameters around 6 nm. Scanning electron microscopy and energy dispersive X-ray spectroscopy corroborated the presence of silver disseminated over the surface of hydroxyapatite nanopowders. All HAp-AgNPs composites demonstrated excellent antibacterial effect even at lower silver concentration. HAp-AgNPs composites have a higher possibility for medical applications focused no the control of microorganisms with drug-resistance.

Chengcai Huang, Rui Qin, Linli Zhang, Muqing Qiu and Linfa Bao

Biochar is thought to be a good adsorption material for the adsorption of heavy metals. In this study, biochar derived from Torreya grandis nutshell was prepared through to be pyrolyzed under oxygen limited conditions in a muffle furnace. The adsorption experiments of Cr(VI) were carried out. Through Elemental Analyzer, Specific Surface Area Meter, Scanning Electron Microscopy, Transmission Electron Microscopy and Fourier Transform Infrared Spectroscopy, a fundamental understanding of the physical and chemical properties of biochar was gained. The results showed that it was a smooth sheet and irregular arrangement structure. The elements of C, H, O and N of biochar are 45.21%, 5.18%, 46.16% and 3.45% respectively. BET specific surface area of biochar is 42.24 m2/g. A lot of oxygencontaining functional groups (– OH, COO –, – C – OH and so on ) appeared on the surface of biochar. It can be described by the pseudo-second order kinetic rate model and Langmuir isotherm model. The adsorption process is a monolayer chemical process. The adsorption mechanism of biochar on heavy metal Cr(VI) contains the electrostatic attraction between biochar and Cr2O7 2-, HCrO4 - and CrO4 2- ions in aqueous solution and complexation reaction of oxygen-containing functional groups (– OH, – COOH and so on) and Cr2O7 2- , HCrO4 - and CrO4 2- ions on the surface of biochar.

Clément Cabriel, Nicolas Bourg, Pierre Jouchet et al.

3D single molecule localization microscopy suffers from several experimental biases that degrade the resolution or localization precision. Here the authors present a dual-view detection scheme combining supercritical angle fluorescence and astigmatic imaging to obtain precise and unbiased 3D super resolution images.

Sebastian Feliu, Lucien Veleva, Federico García-Galvan

In this work, the corrosion behaviors of the AZ31B alloy in Ringer&#8217;s solution at 20 &#176;C and 37 &#176;C were compared over four days to better understand the influence of temperature and immersion time on corrosion rate. The corrosion products on the surfaces of the AZ31B alloys were examined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Electrochemical impedance spectroscopy (EIS) provided information about the protective properties of the corrosion layers. A significant acceleration in corrosion rate with increasing temperature was measured using mass loss and evolved hydrogen methods. This temperature effect was directly related to the changes in chemical composition and thickness of the Al-rich corrosion layer formed on the surface of the AZ31B alloy. At 20 &#176;C, the presence of a thick (micrometer scale) Al-rich corrosion layer on the surface reduced the corrosion rate in Ringer&#8217;s solution over time. At 37 &#176;C, the incorporation of additional Mg and Al compounds containing Cl into the Al-rich corrosion layer was observed in the early stages of exposure to Ringer&#8217;s solution. At 37 &#176;C, a significant decrease in the thickness of this corrosion layer was noted after four days.

Zhao Wang, Ting Luo, Amin Cao et al.

In this study, a series of diblock glycopolymers, poly(6-O-methacryloyl-d-galactopyranose)-b-poly(6-cholesteryloxyhexyl methacrylate) (PMAgala-b-PMAChols), with cholesterol/galactose grafts were prepared through a sequential reversible addition-fragmentation chain transfer (RAFT) polymerization and deprotection process. The glycopolymers could self-assemble into aggregates with various morphologies depending on cholesterol/galactose-containing block weight ratios, as determined by transmission electronic microscopy (TEM) and dynamic laser light scattering (DLS). In addition, the lectin (Ricinus communis agglutinin II, RCA120) recognition and bovine serum albumin (BSA) adsorption of the PMAgala-b-PMAChol aggregates were evaluated. The SK-Hep-1 tumor cell inhibition properties of the PMAgala-b-PMAChol/doxorubicin (DOX) complex aggregates were further examined in vitro. Results indicate that the PMAgala-b-PMAChol aggregates with various morphologies showed different interaction/recognition features with RCA120 and BSA. Spherical aggregates (d ≈ 92 nm) possessed the highest RCA120 recognition ability and lowest BSA protein adsorption. In addition, the DOX-loaded spherical complex aggregates exhibited a better tumor cell inhibition property than those of nanofibrous complex aggregates. The morphology-variable aggregates derived from the amphiphilic glycopolymers may serve as multifunctional biomaterials with biomolecular recognition and drug delivery features.

Terenina N. B., Kreshchenko N. D., Mochalova N. B. et al.

The serotoninergic and FMRFamidergic nervous system of the attachment organs of trematodes were examined using immunocytochemical techniques and confocal scanning laser microscopy. Adult trematodes from eight families as well as cercariae and metacercariae from ten families were studied. TRITC-conjugated phalloidin was used to stain the muscle fibres. The serotonin- and FMRFamide-immunoreactive (IR) nerve cells and fibres were revealed to be near the muscle fibres of the oral and ventral suckers of the trematodes and their larvae. The results indicate the important role of neurotransmitters, serotonin and neuropeptide FMRFamide in the regulation of muscle activity in the attachment organs of trematodes and can be considered in perspective for the development of new anthelmintic drugs, which can interrupt the function of the attachment organs of the parasites.

A. USTIONE, D.W. PISTON