Scanning Electron Microscopy Examination Research Articles

Case report: Exploring autosomal recessive woolly hair: genetic and scanning electron microscopic perspectives on a Japanese patient

Woolly hair (WH) is a hair shaft anomaly characterized by tightly curled hair that typically stops growing at a few inches. Autosomal recessive WH (ARWH; OMIM no. 278150/604379/616760) has been reported to be caused by variants in genes coding lysophosphatidic acid receptor 6 (LPAR6), lipase H (LIPH), or keratin 25 (KRT25). In this study, we conducted a scanning electron microscopic (SEM) examination of the hair of a 3-year-old Japanese ARWH patient. The SEM revealed that her affected hair had an irregular and rough cuticle compared to her mother’s hair. Many irregular small projections and longitudinal grooves were seen on the surface of the patient’s hair shaft, and some free margins of the hair cortex were raised or serrated. Her hairs were oval-shaped on the cross-section. Mutation analysis revealed a homozygous pathogenic variant (c.736 T > A; Cys246Ser) in exon 6 in LIPH. In our clinic, we identified three additional cases with the homozygous Cys246Ser variant and one case with compound heterozygous variants in LIPH: Cys246Ser and c.671C > G (Pro224Arg). Consequently, genetic analyses, including genotype–phenotype correlation involving rare LIPH variants, have become more crucial in the Japanese population.

Eco-Friendly Production of Metal Nanoparticles Through Plant Extract Besides Their Assessment of Antibacterial, and Antifungal activity

A green-synthesis method for silver nanoparticles (Ag NPs) is a scientific breakthrough. Using sunflower plant extracts, this approach uses metallic and botanical synergy. Naturally occurring and renewable extracts reduce, chelate, stabilize, bind, and precipitate. The Ag nanoparticles' X-ray diffraction (XRD) crystal structure was cubic. Average nanoparticle crystallite size was 31.18 nm. Energy-dispersive X-ray spectroscopy (EDX) detected silver. Field Emission Scanning Electron Microscope (FESEM) examination revealed that the particles were Ag (silver) and spherical, averaging 31.23nm. Diffuse Reflectance Spectroscopy also indicated a 2.7 eV optical gap. Using many characterization methods, nanostructured silver was synthesized during this procedure. Biological efficacy assays can evaluate hierarchically porous silver's antibacterial properties. In the previous five years, strategies against Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus mutans, Ecoli, and Candida albicans, Penicillium spp., and Aspergillus spp. were essential. Data demonstrates that these structures are attractive antibacterial choices. A majority of Ag NPs are natural bacterium substitutes for Staphylococcus aureus, pseudomonas aeruginosa, Streptococcus mutans, and Ecoli. Also against various fungi: The immune systems of immunocompromised hosts are threatened by yeasts such Candida albicans, Penicillium, and Aspergillus.measured. It calls into doubt the study's efficacy in antibacterial and other applications.

Occurrence of Stenurus globicephalae (Nematoda: Pseudaliidae) in the blowhole of Globicephala macrorhynchus (Cetacea: Delphinidae) in Tasmania, Australia.

Information about parasites of cetaceans in Australia is scarce and mostly opportunistic. The morphology of specimens of the metastrongyloid Stenurus globicephalae Baylis & Daubney, 1925 (Nematoda: Pseudaliidae), collected from the blowhole of a pilot whale Globicephala macrorhynchus Gray, 1846 (Cetacea: Delphinidae) off northern Tasmania, Australia, were studied. Light and scanning electron microscopical examinations enabled a detailed redescription of this nematode species, including corrections of some inaccuracies in previous species descriptions, particularly those concerning cephalic and caudal structures. The presence of numerous ventrolateral oblique muscle bands, characteristic of the males of S. globicephalae, is reported for the first time. This is the second finding of this nematode parasite, in a different host species, in Tasmania.

Shedding Light on the Failure Factors of Subsea Critical Fastener Bolts

Offshore facilities, such as oil and gas rigs, wind turbines, and related subsea equipment, typically use flanges fastened using bolts and nuts as the main connectors. In this study, multidisciplinary parameters, namely the preload torque used to tighten bolts, simulated subsea water currents, water temperature, and impressed current cathodic protection, were applied to ASTM A193 B7 bolts. An experimental supervisory control and data acquisition system was designed to obtain measurements every 5 min throughout a 21-day experiment. Finite element analysis was performed to predict the structurally vulnerable areas of the bolts. A strong correlation was found between the reference electrode readings and the measured electrical current, tightening torque, and water temperature. As the water temperature rises during the day, the reference electrode reading becomes less negative and the electrical current decreases. Subsea water currents cause about a four-time increase in the bolt corrosion rate, with unprotected bolts suffering a nine-time-higher corrosion rate than protected bolts. A unique supply–demand interaction is observed; less protection is supplied to areas with lower corrosion rates (lower demand for protection). Finally, scanning electron microscopy examination reveals new insights into the failure mechanisms of subsea bolts.

Low-Temperature Synthesis of Bi2S3 Hierarchical Microstructures via Co-Precipitation and Digestive Process in Aqueous Medium.

Bismuth sulfide (Bi2S3) nanostructures have gained significant attention in the fields of catalysis, optoelectronics, and biomedicine due to their unique physicochemical properties. This paper introduces a simple and cost-effective method for producing Bi2S3 microstructures at low temperatures (25 and 70 °C). These microstructures are formed by the hierarchical self-assembly of Bi2S3 nanoparticles, which are typically 15-40 nm in size. The nanoparticles are synthesized by the co-precipitation of thioglycolic acid, thioacetamide, and bismuth nitrate in water. The study delves into the phase composition and morphological evolution of the microstructures, concerning the chemical composition of the solution and the synthesis temperature. X-ray analysis has confirmed the formation of single-phase bismuthinite Bi2S3. The synthesis process generates primary building blocks in the form of 15-40 nm Bi2S3 nanocrystals, which then go through a hierarchical self-assembly process to produce a range of micrometer-sized structures. A scanning electron microscopy examination revealed that the primary nanoparticles self-assemble into quasi-1D worm-like nanostructures, which then self-assemble to create sponge-shaped microstructures. These structures subsequently self-organize and refine into either flower- or dandelion-like microstructures, mostly depending on the synthesis temperature and the chemistry of the digestion medium.

Fabrication of GNPs sprayed carbon fiber and its effects on the interfacial and mechanical behavior of reinforced epoxy multiscale laminated composite

AbstractThe current research compares the effects of modifying carbon fiber [via spraying graphene nanoplates (GNPs)] and/or GNPs reinforcement on the mechanical and interfacial behavior of carbon fiber epoxy composites. Using a spraying method, the epoxy matrix was reinforced, and carbon fiber was modified with 0.2 and 1 wt% of GNPs, respectively. Tensile, interlaminar, and dynamic mechanical analyses (DMA) tests were conducted on the composite to assess the role of GNPs in enhancing mechanical, interfacial, and thermomechanical properties. The obtained results indicate that the spraying technique effectively enhanced the ultimate tensile strength (UTS) and interlaminar fracture toughness (ILFT) of the composite. The UTS improved by 31%, while the ILFT significantly improved by 38%. Additionally, assessing the modulus gradient through the interface shows improved interfacial interaction between modified carbon fiber and reinforced epoxy. Scanning electron microscopy examination of the fractured surfaces indicated that the existence of nanofillers with high surface area contributed to significant improvements in adhesion between the modified fiber and reinforced epoxy matrix, leading to enhanced interfacial, mechanical, and thermomechanical properties of CFRPs for structural applications.Highlights Incorporation of surface modified carbon fibers and GNPs reinforcement in the epoxy matrix to enhance the interfacial interaction. Evaluation of the effects of GNP nanofiller on interfacial and mechanical performance of the composite. Fracture surfaces in ILSS, tensile, and mode I test were analyzed using FESEM. Utilization of nanoscale modulus mapping for the fiber‐matrix interface assessment.

Carbon Fiber Polymer Reinforced 3D Printed Composites for Centrifugal Pump Impeller Manufacturing

Centrifugal pumps are used extensively in various everyday applications. The occurrence of corrosion phenomena during operation often leads to the failure of a pump’s operating components, such as the impeller. The present research study examines the utilization of composite materials for fabricating centrifugal pump components using additive manufacturing as an effort to fabricate corrosion resistant parts. To achieve the latter two nanocomposite materials, carbon fiber reinforced polyamide and carbon fiber reinforced polyphenylene sulfide were compared with two metal alloys, cast iron and brass, which are currently used in pump impeller manufacturing. The mechanical properties of the materials are extracted by performing a series of experiments, such as uniaxial tensile tests, nanoindentation and scanning electron microscope (SEM) examination of the specimen’s fracture area. Then, computational fluid dynamics (CFD) analysis is performed using various impeller designs to determine the fluid pressure exerted on the impeller’s geometry during its operation. Finally, the maximum power rating of an impeller that can be made from such composites will be determined using a static finite element model (FEM). The FEM static model is developed by integrating the data collected from the experiments with the results obtained from the CFD analysis. The current research work shows that nanocomposites can potentially be used for developing impellers with rated power of up to 9.41 kW.

Friction stir consolidation for recycling AA6061 chips with its metal flow investigation for billet production

This study aims to produce a billet from AA6061 chips recycling by adopting friction stir consolidation (FSC) technique. AA6061 was used to form different shapes of chips with a thickness of 1 mm. The billet was produced by stacking and forming the chips inside the cylindrical die adopting the friction stir consolidation technique with a rotating tool. Three parameters were considered: preheating time, rotating speed of tool, and depth of plunging, with three levels for each parameter. A Taguchi strategy was implemented to design the experiments (DOE) and analyse the billet properties. The billet cross-section was examined by the optical and scanning electron microscope examinations. The billet was successfully produced by recycling the AA6061 chips. The production mechanism occurred by grains elongating, metal flow, and welding the chip’s boundaries with the applied pressure and input heat. Minor defects such as cracks and porosities were found in the entire surfaces of the billets. The presence of the defects relied on the process variables. The billet's surface appearance or quality depended on the tool's depth of plunging. The tool's revolving speed and depth of plunge determined the process's temperature. The depth of plunging was the most influential parameter on the surface quality of the billets. Raising the depth of plunging and rotational speed generated higher heat input, which increased the weldability between the chip’s boundaries and reduced the surface defects. Regions of sufficient input heat during the stir forming process exhibited complete welding between the chip’s boundaries without defects. The best forming condition achieved among all runs was at (1800 rpm rotational speed, 1 min. preheating time, and 35 mm depth of plunging). For the first time, the friction stir consolidation process produced the billets by recycling the AA6061 chips without any material loss.

Effect of dehydration method on the micro- and nanomorphological properties of bacterial cellulose produced by Medusomyces gisevii on different substrates

Many important properties of bacterial cellulose (BC), such as moisture absorption capacity, elasticity and tensile strength, largely depend on its structure. This paper presents a study on the effect of the drying method on BC films produced by Medusomyces gisevii using two different procedures: room temperature drying (RT, (24 ± 2 °C, humidity 65 ± 1%, dried until a constant weight was reached) and freeze-drying (FD, treated at − 75 °C for 48 h). BC was synthesized using one of two different carbon sources—either glucose or sucrose. Structural differences in the obtained BC films were evaluated using atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray diffraction. Macroscopically, the RT samples appeared semi-transparent and smooth, whereas the FD group exhibited an opaque white color and sponge-like structure. SEM examination showed denser packing of fibrils in FD samples while RT-samples displayed smaller average fiber diameter, lower surface roughness and less porosity. AFM confirmed the SEM observations and showed that the FD material exhibited a more branched structure and a higher surface roughness. The samples cultivated in a glucose-containing nutrient medium, generally displayed a straight and ordered shape of fibrils compared to the sucrose-derived BC, characterized by a rougher and wavier structure. The BC films dried under different conditions showed distinctly different crystallinity degrees, whereas the carbon source in the culture medium was found to have a relatively small effect on the BC crystallinity.Graphical

Understanding seawater-induced fatigue changes in glass/epoxy laminates: A SEM, EDS, and FTIR study

Composite polymeric materials have exhibited significant advantages when operating in hostile conditions such as the marine environment. However, there is a lack of information concerning three-dimensional variations induced by prolonged exposure to seawater in composite structures and their impact on fatigue performance. Thus, this study aims to investigate the effects of long-term exposure to natural seawater on both the fatigue strength and three-dimensional chemical changes of GFRP laminates. Fatigue tests were conducted under uniaxial cyclic loading at a stress ratio R = 0.1, considering three groups of specimens: a control group not immersed in natural seawater, a group immersed for 230 days in natural seawater, and a group immersed for 910 days in natural seawater. After the tests, fracture surfaces were analysed using scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS). SEM examination revealed the microstructural occurrence of fibre-matrix debonding, reducing the load transfer between the fibre and matrix, contributing to the fatigue life decrease in immersed specimens. The fatigue results revealed that the reduction in fatigue life of the specimens immersed for 230 days was approximately 66 % of that observed in the control specimens increasing to 95 % when the immersion period extended to 910 days. Moreover, the effect of immersion time on the chemical structure of various regions within the specimens was assessed using Fourier-transform infrared (FTIR) spectroscopy. The main findings suggest the existence of a concentration gradient within the laminate and that regions near permeable surfaces are more vulnerable to chemical changes compared to regions located further away, even after reaching saturation.

Effect of Zinc Oxide Nanostructure on the Electrical Conductivity of Polyvinyl Alcohol (PVA) Thin Films

Zinc oxide nanoparticles in the form of particles and rods were synthesized using the hydrothermal method. The scanning electron microscopy (SEM) examination was performed. The results of the SEM tests showed the nanoscale size of zinc oxide nanoparticles was (75 nm) for particles and (150 nm) for rods. An X-ray diffraction examination was carried out, and a comparison was made between the diffraction pattern of the ZnO nanoparticle and the rods. The results showed that the ZnO nanoparticle is in the hexagonal wurtzite phase of the structure of the particles and rods. Zinc oxide nanoparticles (particles and rods) produced by the hydrothermal method have been used as an additive in polyvinyl alcohol (PVA) polymer matrix to form PVA–ZnO NPs composite thin films. The optical properties of the membrane were studied using ultraviolet–visible examination, which showed a decrease in the energy gap of the composite thin film compared to the pure membrane. While the electrical properties of composite thin film, including resistivity, mobility and majority carrier charge carriers of composite thin film, were measured using the Hall effect measurement. The results showed that zinc oxide nanoparticles have a higher conductivity than nanorods.

Depriving friction stir weld defects in dissimilar aluminum lap joints

The contemporary automotive industry increasingly incorporates composite materials and innovative joining techniques to meet customer demands for lightweight, high-strength alloys. This research explores the feasibility of using friction stir welding (FSW) methods to fabricate dissimilar aluminum nanocomposite lap joints, integrating Al2O3 nanoparticles into the weld nugget. Lap joints were prepared with varying tool rotation speeds (1000–1600 rpm) and the mechanical and metallurgical behaviors of AA6061–AA7075-T6/Al2O3 lap joints were examined. The inclusion of filler material in the weld joint resulted in an 18% increase in shear strength compared to joints without filler. Dynamic crystallization impeded grain boundaries and reduced grain size in the weld stir zone (SZ), with the most enhanced mechanical characteristics observed at a tool rotation speed of 1400 rpm. The shear strength at 1400 rpm was 5780 N, representing a 17% increase compared to joints prepared at 1000 rpm. Field emission scanning electron microscopic examination revealed evenly dispersed Al2O3 nanoparticles within the weld zone, supporting the lap shear test results. Notably, joints created at lower (1000 rpm) and higher tool rotational speeds (1600 rpm) exhibited brittle fracture behavior. The addition of Al2O3 significantly improved lap joint tensile strength due to its uniform dispersion in the SZ. Increasing the FSW tool rotational speed from 1000 to 1400 rpm facilitated nanoparticle dispersion, further enhancing lap joint strength.

Strontium-Doped Hydroxyapatite Coating Improves Osteo/Angiogenesis for Ameliorative Graft-Bone Integration via the Macrophage-Derived Cytokines-Mediated Integrin Signal Pathway.

Polyethylene terephthalate (PET) artificial ligaments, renowned for their superior mechanical properties, have been extensively adopted in anterior cruciate ligament (ACL) reconstruction surgeries. However, the inherent bio-inertness of PET introduces formidable barriers to graft-bone integration, a critical aspect of rehabilitation. Previous interventions, ranging from surface roughening to chemical modifications, have aimed to address this challenge; however, consistently effective techniques for inducing graft-bone integration remain scarce. Our study employed advanced surface-coating methodologies to introduce strontium-doped hydroxyapatite (SrHA) onto PET ligaments. Detailed scanning electron microscopy (SEM) examinations revealed a uniform and integrative coating of SrHA on PET fibers. Furthermore, spectroscopic analysis confirmed the steady release of strontium ions from the coated surface under physiological conditions. In-depth cellular studies proved that extracellular strontium emanating from SrHA-coated PET (PET@SrHA) ligaments actively steers the M2 macrophage polarization. Additionally, macrophages (Mφs) manifested a heightened secretion of prohealing cytokines when exposed to PET@SrHA. Subsequent investigations showed that these cytokines acted as mediators, activating integrin signaling pathways among macrophages, vascular endothelial cells, and osteoblasts. As a direct consequence, an increased rate of angiogenesis and osteogenic differentiation was observed, vital for graft-bone integration following ACL reconstruction with PET@SrHA ligaments. From a biochemical standpoint, our results pinpoint strontium ions as influential immunomodulators, sculpting the graft-bone interface's immune environment. This insight presents the SrHA-coating technique as a viable therapeutic strategy, holding sound promise for improving angiogenesis and osseointegration outcomes during ACL reconstruction using PET-based grafts.

The leaf micromorphology and anatomy of gamba grass, Andropogon gayanus Kunth (Poaceae: Panicoideae)

Context Andropogon gayanus, commonly known as gamba grass, is one of the declared weeds of national significance in Australia. Past studies have focused on gross morphology of root structures, biogeochemical behaviour, and ecology, but there has been limited work on comparative descriptions of leaf micromorphology and anatomy. Aims We investigated and described its leaf micromorphology and anatomy to understand weed biology and ecophysiology. Methods Optical and scanning electron microscope examination of the adaxial and abaxial leaf surfaces of A. gayanus was carried out. We identified and generated a list of morphological characters that were used to compare several dried herbarium specimens of A. gayanus. Key results The leaf characters were consistent across all specimens examined, with minor differences in leaf pubescence, indicating this could be a plastic trait. Conclusions Andropogon gayanus leaves are well adapted to wet and dry tropical conditions. Plasticity in leaf surface pubescence possibly enhances its adaptability, increasing its success as a weed in Australian ecosystems. The success of A. gayanus in Australia could be because the environment compares favourably with the native environment of the species in Africa, where it has adapted to extremes of wet and dry conditions over a large geographical range. Implications Plant morphological and taxonomic studies of A. gayanus focused on describing characters of spikelets and caryopses are recommended to understand how reproductive structures aid in its successful proliferation.

Detrimental Effects of Sterilization Types on Single-Use Coronary Angioplasty Catheters for Reuse: An Electron Microscopic Study.

Reuse of medical devices poses risks concerning technical issues and patient safety. In this study, we aimed to examine the structural changes in catheters that occur due to the reuse with the aid of electron microscopy. The effects of hydrogen peroxide (HP) and ethylene oxide (EO) sterilization on four percutaneous transluminal coronary angioplasty (PTCA) catheters and control PTCA catheters were examined by scanning electron microscope (SEM). Each catheter sample was divided into four parts during the SEM examination, and a total of 20 pieces were examined. Catheters were reprocessed through every regular sterilization step and used solely for the study, not in patients. Statistical evaluations of histological scoring made on images obtained from scanning electron microscopic images were made using the GraphPad Prism 8 program. Electron microscopical examination showed that HP sterilization caused more robust and deeper lines compared to EO. These distortions increased directly with the increase in the reprocessing cycle. In EO, no significant damage was detected within five cycles in contrast to HP; however, the harmful effects of EO were seen over five cycles. Unprocessed samples had no damage. Outer and inner deterioration was significantly higher in the EO>5 group and HP>5 group than in the control group. However, the bacterial contamination score in the EO>5 group was higher than the control group. Our findings showed that HP and EO sterilizations caused some deterioration in the inner and outer surfaces of PTCA catheter samples. We recommend reprocessing using EO, the least damaging method, when necessary, and paying attention not to exceed five cycles when necessary.

Adapting a phenomenological model for predicting acoustical behaviour of Camellia sinensis/Ananas comosus/E-glass fibre-blended epoxy hybrid composites

Developing a hybrid phenomenological model for predicting the sound absorption coefficient of a pineapple leaf fibre/waste tea leaf fibre/glass fibre/epoxy-based natural fibre-reinforced hybrid composites is the predominant topic of this article. Phenomenological models excel at extrapolating characteristic impedance and wave number whereas empirical models require fewer inputs but overlook wave propagation in pores. Existing models apply only to single-fibre-reinforced composites, necessitating the creation of a hybrid model for hybrid composites. The developed hybrid Zwikker–Kosten and Johnson–Champoux–Allard model shows good agreement with experimental data across the frequency range, with standard deviations of 0.001–0.029 and percent deviations of 1.11%–11.43%. The overall noise reduction coefficient between the model and experiments is 0.31 vs. 0.30, with a 3.33% deviation. Furthermore, the application of alkali treatment increased the surface roughness which in turn, enhanced the sound absorption capabilities of these composites. The increased fibre roughness also amplified friction between fibres and sound waves, resulting in higher sound absorption coefficients. In addition, X-ray diffraction, thermal stability (thermogravimetric analysis and differential scanning calorimetry), and scanning electron microscopy examinations were performed on the designated composition (5% by weight of pineapple leaf fibre and 25% by weight of waste tea leaf fibre) of the pineapple leaf fibre/waste tea leaf fibre/glass fibre/epoxy-based natural fibre-reinforced hybrid composite.

Scanning Electron Microscopy Analysis of Kenaf Coir Epoxy Reinforced Carbon Nanotubes Nanoparticles Hybrid Composite

Ecological awareness and sustainable development have attracted researchers’ focus on composites developed using natural fibers. Consequently, natural fiber polymer composites are flattering and increasingly prominent for use and research. Fiber-reinforced composites inhibit considerable benefits, in conjunction with high strength and lesser weight, simpler fabrication, biodegradability, lesser cost of production, and so on. Natural fiber offers good properties, but it requires proper matrix interface bonding along with effective synergy amongst each matrix-fibre combination. In the case of the hybrid composite proposed in this research, analytical modeling has been carried out and compared with the previous literature, in our previously published research [Parashar, S. and Chawla, V., 2022. Kenaf-coir based hybrid nanocomposite: AN analytical and representative volume element analysis. Engineering Solid Mechanics, 11(1), pp.103–118]. The present paper investigates the composite proposed in the research for scanning electron microscopy examinations, using an S3400M Scanning Electron Microscope. Each of the specimens has been cut to the necessary dimensions for SEM examination. The micrographs have been created with a high voltage of 20 kV. The broken surface of the tensile specimens of the composite samples was investigated using SEM. According to the findings of SEM and analytical modeling it has been observed that, combining nanoparticles of CNT as filler and kenaf-coir as fiber reinforcement results in a composite material with good interfacial adhesion betwixt matrix and fibers, high strength, and mechanical capabilities, to make hybrid composites for various industrial and automotive applications compared to composite present in the previous literature. The hybridization effect has also been evaluated for the composite, which depicts the higher tensile failure strain of the proposed hybrid composite.

Biocomposites of Poly(Lactic Acid) and Microcrystalline Cellulose: Influence of the Coupling Agent on Thermomechanical and Absorption Characteristics.

In this study, poly(lactic acid) (PLA) and microcrystalline cellulose (MCC)-based green biocomposites were developed using a solution casting technique. Essentially, the bonding between PLA and MCC is quite feeble; therefore, the current study is conducted to strengthen the bonding by incorporating a coupling agent, thereby enhancing the overall quality of the biocomposites. Thus, the present study aimed to examine the influence of combined coupling agents-maleic anhydride (MAH) and maleic acid (MA) (MAH-MA)-on the properties of polylactic acid (PLA)/microcrystalline cellulose (MCC) biocomposites. The investigation also encompassed an examination of the impact of MCC loading (2, 3, and 5% w/w) into a PLA matrix. The Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) examination revealed the interfacial interaction and adhesion among MCC, PLA, and coupling agents and the formation of biocomposites. The incorporation of MAH-MA led to improved mechanical properties of the PLA/MCC biocomposites. Furthermore, the incorporation of MAH-MA into the PLA/3 wt % MCC composite exhibited enhancements in both the tensile strength and tensile modulus, accompanied by a reduced elongation at break. In addition, it is worth noting that the thermogravimetric analysis (TGA) curve of the PLA composite with 3% w/w of MCC and MAH-MA displayed a significant decrease in weight beyond a temperature threshold of 492.65 °C. The water absorption demonstrates that the incorporation of MAH-MA into the PLA/MCC composite led to advantageous water barrier characteristics. The observed improvements were attributed to the efficient dispersion of MCC at the most favorable amount of coupling agents, along with the chemical interactions involving grafting and esterification between MCC and the MAH-MA coupling agent. Furthermore, the incorporation of MAH-MA into the PLA/3% (w/w) MCC composite exhibited enhancements in both the tensile strength and tensile modulus, accompanied by a reduction in the elongation percentage at break. The experimental results about water absorption demonstrate that the incorporation of MAH-MA into the PLA/MCC composite led to advantageous water barrier characteristics. These improvements were attributed to good MCC dispersion and the chemical interactions involving grafting and esterification between the MCC and the MAH-MA coupling agent.

Palynology of Taxa of Crepis L. Genus Growing in Çanakkale, Türkiye

This study investigated the pollen morphology of the taxa belonging to the genus Crepis L. collected from various localities in Çanakkale in 2015. Wodehouse (1935) and Acetolysis (Erdtman, 1960) methods were used in the research. Pollen morphologies of 3 species and two subspecies belonging to the Crepis L. genus were defined according to light microscopy (LM) and scanning electron microscopy (SEM) examinations. In LM, pollens are monad, radially symmetrical and isopolar. Pollens are suboblate and oblate spheroidal, Amb shape is inter-hexagonal-subtriangular. The pollen of the genus is tricolporate. The view from the equator is circular and oval. In the examinations made with LM, the ornamentation is echinulophate. Pollen has 15 lacunae as 3 poral, 6 abporal, 6 paraboral. Ornamentation is echinulophate; the tectum surface is microperforate. SEM micrographs of C. smyrnaea and C. commutata pollen show depressions at the corners of the polar field. The collapses are located on the paraboral lacunae and are distinctly lacuna-like. As a result, in this study, palynological features of C. smyrnaea DC., C. micrantha Czerep., C. commutata (Spreng.), C. reuterana Boiss. & Heldr. subsp. reuterana taxa were studied for the first time. C. smyrnaea DC. ex Froel. was collected for the first time in Çanakkale within the scope of this study, according to the type records in Flora of Turkey.

Discovery of late Quaternary giant magnetofossils in the Bay of Bengal

Unusually large and enigmatic giant magnetofossils are well-documented in sediments deposited during and surrounding climatic events such as the Paleocene-Eocene Thermal Maximum (~56 Ma) and Middle Eocene Climatic Optimum (~40 Ma). However, the absence of giant magnetofossil modern analogues raises intriguing questions about their origin and formation mechanism. In this study, we report the discovery of giant magnetofossils within late Quaternary sediments retrieved from the Bay of Bengal (BoB), the youngest giant magnetofossils yet reported. First-order reversal curve diagrams of BoB sediments display a central ridge feature, a characteristic magnetic signature of non-interacting single domain magnetofossils. Scanning electron microscopy examinations reveal giant magnetofossils with needle, spindle, bullet, and spearhead shapes. We use high-resolution transmission electron microscopy, with electron diffraction and energy dispersive spectrometry, to confirm their distinctive morphologies and magnetite crystal structure. Our environmental magnetic and geochemical data suggest that an influx of fluvially derived reactive iron and organic carbon, combined with persistent suboxic conditions, supported the proliferation of giant magnetofossil-producing organisms. The discovery of a modern analogue to ancient giant magnetofossils expands our understanding of their temporal distribution within the geological record and is a promising step toward elucidating the nature of the organisms responsible for their formation.