Transmission Electron Microscopy Data Research Articles

Microstructural changes induced in advanced tungsten grades under high temperature neutron irradiation

Recent studies addressing the change of mechanical properties after high temperature irradiation of tungsten have reported substantial increase of the ductile to brittle transition temperature as well as increase of the hardness. In this work, we performed microstructural analysis by means of transmission electron microscopy (TEM) on various tungsten grades earlier exposed to high temperature neutron irradiation at 1200 °C up to 1 dpa. The latter corresponds to the expected irradiation temperature on the surface of a tungsten monoblock during the steady state operation in ITER. TEM was applied to five tungsten (W) materials including ITER specification pure W and precipitate strengthened W alloys. The analysis of TEM data coupled with its discussion led to a number of important conclusions regarding the damage induced at 1200 °C neutron irradiation such as: (i) weak effect of recrystallization on the accumulation of the lattice damage; (ii) promising results on the tolerance of damage accumulation in W-Y2O3 grade and (iii) internal oxidation of TiC particles which may contribute to the huge increase of the irradiation induced hardening.

Water–Rock Interaction Processes in Tíscar and Larva Active Faults (Betic Cordillera, SE Spain)

A hydrochemical and mineral study of groundwaters and damaged rocks from the Tíscar and Larva fault zones (Betic Cordillera, Iberian Peninsula) was carried out in order to (a) describe the physical and chemical properties of the groundwaters; (b) recognize significant locations with deep-origin fluids related to active tectonics; (c) and to describe the water–rock interaction and the neoformation of clay mineral processes and their importance in the seismicity of the faults. A sampling campaign was completed between November 2012 and November 2013, during which data were obtained from 23 different groundwater sites in the fault areas. Two main groups of waters were distinguished: (a) Ca2+-Mg2+-HCO3− facies characterized by poor conductivity and salinity; and (b) saline waters (up to 30 meq/L) rich in Ca2+-Mg2+-SO4-Cl− and with an elevated conductivity (frequently > 1000 μS/cm). In addition, a minor group of saline and warm waters (T > 16.5 °C) was found to be Na+-rich and show moderately high B values (>0.33 ppm), and which mig ht be hosted in aquifers deeper than the two main groups. This group of deep-origin waters is oversaturated in clay minerals and is in equilibrium for Ca-Mg carbonate minerals. X-ray diffraction and scanning and transmission electron microscopy data corroborate the crystallization forecast of authigenic smectite, which appears as thin films coating carbonate fragments. The origin of smectite is related to the fragile strain and thermal–fluid–mineral interactions in fault rocks. Smectite could lubricate carbonate rocks, which favor creep deformation versus seismic slip. This work provides locations where groundwater physico-chemical properties and composition suggest tectonic fault activity.

Green synthesis of Ag nanoparticles from Verbascum insulare Boiss. and Heldr.: Evaluation of antimicrobial, anticancer, antioxidant properties and photocatalytic degradation of MB

In recent years, due to the environmental friendliness of nanoparticle production, biosynthesis methods using plant extracts and possible physical, chemical, thermal and biological properties of the synthesized nanoparticles are frequently the subject of research. In the present study, hydrothermally assisted synthesis of Ag nanoparticles using twig-leaf extract of Verbascum insulare Boiss. and Heldr., (VIE-AgNPs) a plant endemic to Turkey, was successfully carried out for the first time in this study. The presence of 24 of the 53 phytochemicals investigated in the content of the extract of Verbascum insulare Boiss. and Heldr. (VIE) determined by the LC-MS/MS system was detected. In addition, the amount of phenolic substance involved in reduction was found to be 60.42 ± 9.11 µg Gallic acid equivalent/mg-extract. The synthesized AgNPs were characterized by UV–visible spectra (UV–vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transforms infrared spectroscopy (FTIR), and X-ray diffraction (XRD). In particular, the surface plasmon band observed at 422 nm, the characteristic peaks observed in XRD, and the bond energy values seen in XPS strongly confirmed the formation of AgNPs. XRD and TEM data showed that AgNPs had an average size range of 25–30 nm. FTIR data indicated the presence of some herbal agents on the surface of AgNPs. The properties of the VIE-AgNPs were compared in vitro with chemically produced AgNPs (C-AgNPs). The OSI level of C-AgNPs was 87.78 ± 1.75 AU, while that of VIE- AgNPs was 110.42 ± 7.54 AU. It was observed that the nanoparticle and VIE used in the study had antimicrobial activity. It was determined that its antibacterial activity was stronger than its antifungal activity. When the analyzed inflammatory parameter levels (TNF-α, IL1β, TGF-β, and DEF-β2) were examined, the effect of VIE on inflammation in A549 cells could not be detected. However, it was determined that VIE-AgNPs, one of the nanoparticles used in the study, increased anti-inflammatory levels more than C-AgNPs. When the received data are evaluated together, it can be said that biosynthesized AgNPs suppress proliferation and stimulate apoptosis in cancer cells by increasing oxidative stress and inflammation levels compared to chemical AgNPs, thus showing an anticarcinogenic effect. It was found that VIE-AgNPs could effectively degrade the water pollutant methylene blue (MB) dye. VIE-AgNP mediated 78 % photocatalytic degradation of MB in 180 min. All superior biological properties are thought to be due to the low particle size and the interaction of active components with AgNPs during the biosynthesis process. Because it has been observed that VIE-AgNPs, which have a smaller particle size, have higher biological (cytotoxic, anticarcinogenic, inflammatory, etc.) activities than C-AgNPs. It can be said that AgNPs produced by biosynthesis may have potential use in the production of environmentally friendly, antibacterial/anticarcinogenic materials.

Sonochemical synthesis of gold nanoparticles mediated by potato starch: Its performance in the treatment of esophageal cancer

Abstract Economically viable and eco-friendly potato starch (PS) was employed to synthesize Au NPs under ultrasound irradiation. PS phytochemicals have the function of a green reductant as well as an efficient stabilizer template to cap and synthesize gold nanoparticles. Transmission electron microscopy (TEM), UV-Vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) were applied to investigate the structure of the synthesized PS-Au NPs nanocomposite. FESEM results showed that the obtained Au NPs were spherical and ∼30 nm in diameter; their crystalline nature was detected by XRD and TEM data. PS-Au NP nanocomposite shows high antioxidant effects against DPPH. The colorimetric MTT investigation was followed in the determination of anti-esophageal cancer properties of the PS-Au NP nanocomposite against KYSE-30 and FLO-1 cell lines. The findings indicate that in 3 days, the cancer cell survival percentage in various dilations reduced as much as the PS-Au NP nanocomposite concentration increased. The best anti-cancer effect of the PS-Au NP nanocomposite was reported at 1,000 μg/mL dilation. Through MTT cytotoxicity analysis the half-maximal inhibitory concentration of PS-Au nanocomposite or IC50 values against the KYSE-30 and FLO-1 esophageal carcinoma cells were found as 125 and 176 μg/mL, respectively. The data indicated that these PS-Au NP nanocomposites inhibited esophageal cancer cells more strongly than normal cells.

Structure of Amyloid Peptide Ribbons Characterized by Electron Microscopy, Atomic Force Microscopy, and Solid-State Nuclear Magnetic Resonance.

Polypeptides often self-assemble to form amyloid fibrils, which contain cross-β structural motifs and are typically 5-15 nm in width and micrometers in length. In many cases, short segments of longer amyloid-forming protein or peptide sequences also form cross-β assemblies but with distinctive ribbon-like morphologies that are characterized by a well-defined thickness (on the order of 5 nm) in one lateral dimension and a variable width (typically 10-100 nm) in the other. Here, we use a novel combination of data from solid-state nuclear magnetic resonance (ssNMR), dark-field transmission electron microscopy (TEM), atomic force microscopy (AFM), and cryogenic electron microscopy (cryoEM) to investigate the structures within amyloid ribbons formed by residues 14-23 and residues 11-25 of the Alzheimer's disease-associated amyloid-β peptide (Aβ14-23 and Aβ11-25). The ssNMR data indicate antiparallel β-sheets with specific registries of intermolecular hydrogen bonds. Mass-per-area values are derived from dark-field TEM data. The ribbon thickness is determined from AFM images. For Aβ14-23 ribbons, averaged cryoEM images show a periodic spacing of β-sheets. The combined data support structures in which the amyloid ribbon growth direction is the direction of intermolecular hydrogen bonds between β-strands, the ribbon thickness corresponds to the width of one β-sheet (i.e., approximately the length of one molecule), and the variable ribbon width is a variable multiple of the thickness of one β-sheet (i.e., a multiple of the repeat distance in a stack of β-sheets). This architecture for a cross-β assembly may generally exist within amyloid ribbons.

Quantitative Analysis of Resistance to Deformation of the DNA Origami Framework Supported by Struts.

Nanostructures with controlled shapes are of particular interest due to their consistent physical and chemical properties and their potential for assembly into complex superstructures. The use of supporting struts has proven to be effective in the construction of precise DNA polyhedra. However, the influence of struts on the structure of DNA origami frameworks on the nanoscale remains unclear. In this study, we developed a flexible square DNA origami (SDO) framework and enhanced its structural stability by incorporating interarm supporting struts (SDO-s). Comparing the framework with and without such struts, we found that SDO-s demonstrated a significantly improved resistance to deformation. We assessed the deformability of these two DNA origami structures through the statistical analysis of interior angles of polygons based on atomic force microscopy and transmission electron microscopy data. Our results showed that SDO-s exhibited more centralized interior angle distributions compared to SDO, reducing from 30-150° to 60-120°. Furthermore, molecular dynamics simulations indicated that supporting struts significantly decreased the thermodynamic fluctuations of the SDO-s, as described by the root-mean-square fluctuation parameter. Finally, we experimentally demonstrated that the 2D arrays assembled from SDO-s exhibited significantly higher quality than those assembled from SDO. These quantitative analyses provide an understanding of how supporting struts can enhance the structural integrity of DNA origami frameworks.

Effect of Li on the intrinsic and extrinsic contributions of the piezoelectric response in Lix(Na0.5K0.5)1-xNbO3 piezoelectric ceramics across the polymorphic phase boundary

The temperature-dependent Rayleigh behavior of polycrystalline lead-free Lix(Na0.5K0.5)1-xNbO3 ceramics was characterized to measure the reversible and irreversible piezoelectric response of different compositions with varying Li content. The results revealed that all compositions showed peak values of both reversible and irreversible piezoelectric response near the polymorphic phase boundary. Additionally, depending on the crystal structure, Li content affected the irreversible and reversible contributions. Specifically, at room temperature, there was a notable increase in the irreversible contribution with rising Li content, whereas, within the tetragonal region, the change in Li content predominantly influenced the reversible contributions, resulting in their reduction. These results are discussed in conjunction with temperature-dependent X-ray diffraction and transmission electron microscopy data, which indicated that the lattice distortion and domain structure play an important role in the temperature-dependent variation in the piezoelectric response.

Castaways: the Leeward Antilles endemic spider genus Papiamenta (Araneae: Pholcidae).

Ninetinae is a group of small to tiny short-legged spiders largely restricted to arid habitats. Among daddy-long-legs spiders (Pholcidae) this is by far the least diverse subfamily but this may partly be a result of inadequate collecting, poor representation in collections or scientific neglect. We build on a large recent collection of the ninetine genus Papiamenta Huber, 2000 from the Leeward Antilles and use cytochrome oxidase 1 (COI ) sequences, extensive scanning electron microscopy data, transmission electron microscopy data and karyotyping to analyse this geographically isolated and poorly known island genus. COI sequences support the split between the two morphologically distinct species on Curaçao but genetic distances between these are surprisingly low (7.4-9.8%; mean 8.6%). The type species P. levii (Gertsch, 1982) may include more than one species but COI and morphology suggest conflicting clade limits. A third species, P. bonay Huber sp. nov. is newly described from Bonaire. Our data on sperm ultrastructure and karyology are puzzling as these suggest different phylogenetic affinities of Papiamenta to other genera. Males transfer sperm as individual sperm (cleistosperm), agreeing with the putative closest relatives as suggested by molecular data, the North American genera Pholcophora and Tolteca . The sex chromosome system (X 1 X 2 X 3 Y ) of P. levii , however, is as in the South American Ninetinae genera Gertschiola and Nerudia but different from the putative closest relatives. ZooBank: urn:lsid:zoobank.org:pub:7A6A2E84-3A61-4637-AF6F-0E31A9FA79A8.

Ultra-high piezoelectric properties and ultra-high Curie temperature of Li/Ce-doped La2Ti2O7 ceramics.

The demand for ultra-high-temperature piezoelectric sensors in industrial applications has witnessed a rapid upsurge. In this study, the piezoelectric properties of La2Ti2O7 (LTO) piezoelectric ceramics with a perovskite-like layered structure were enhanced by doping with Li/Ce ions. It was found that a remarkable 300% enhancement in the piezoelectric constant (d33) value was achieved in Li/Ce-doped LTO ceramics compared to their pristine counterparts, reaching 6.4 pC N-1 at room temperature with an ultra-high Curie temperature of 1408 °C. After annealing at 500 °C, the d33 value of the samples can be further improved to 7.4 pC N-1. Moreover, temperature-dependent resistivity measurements indicate that even at 1000 °C, the ceramics exhibit a high resistivity of 8.9 × 105 Ω cm. By combining X-ray diffraction, Raman spectra, transmission electron microscopy and piezoresponse force microscopy data, the enhanced piezoelectricity of the ceramics is attributed to local heterogeneity induced by Li/Ce doping. Our results unequivocally demonstrate the suitability of modified LTO ceramics for ultra-high-temperature piezoelectric applications.

Chromium activated Ca9Al (PO4)7 nanophosphors: synthesis, morphology and dosimetry characteristics

In this article, a sol–gel route was employed to prepare nanophosphor materials including Ca9−x CrxAl (PO4)7 series (where 0.05 ≤ x ≤ 0.5 (mol%)). All subseries were irradiated to a γ- test dose of 5 Gy and the thermoluminescence (TL) response of Cr-activated (0.1 mol%) Ca9Al (PO4)7 sample has the best TL response and was chosen for investigations. The phase, particle size, surface morphology, and elemental mapping of the chosen sample Cr0.1 in comparison with other ones (Cr0.05 and Cr0.5) were scrutinized using x-ray diffraction (XRD), transmission electron microscope (TEM), SEM-EDX mapping, and XPS techniques. XRD profiles showed that all diffraction peaks assigned to the trigonal R 3 c space group and the average of particle sizes obtained by the modified Scherer method and TEM data are closely related. The presence of Cr3+ ions in the Ca9Al (PO4)7 lattice was assured by XPS spectra. Cr0.1 chosen sample was studied after irradiation to different γ-doses and displayed a prominent glow curve at 205 °C ± 3.97 °C. It showed a linear dose–response curve from 200 mGy up to 10 Gy with fading of 24% upon 24 h and almost no significant signal loss for further interval times. The average Zeff value was ∼11 at both 662 and 1250 keV energies making this sample a bone-equivalent material (11.3–11.8). Values of activation energies (eV) calculated by different methods were comparable. Results the dosimetric properties of that the Cr0.1 sample can be surely considered as an additional recommended detector as other available ones in marketing.

New monoclinic ground state of FeSi

By means of ab initio techniques with the hybrid functional we show the existence of a new phase of FeSi with the monoclinic symmetry (space group P21) originated from the B20 cubic structure (space group P213) due to slight orthorhombic distortion, which is turned out to be the ground state. The monoclinic FeSi not only displays the minimum in the total energy, but it is also characterized by a phonon spectrum without imaginary frequencies and by conducting properties (contrary to semiconducting properties of cubic FeSi) with antiferromagnetic ordering and the magnetic moment of 2.3 μB for each Fe atom. These findings are supported by data of X-ray diffraction and high-resolution transmission electron microscopy of ultrathin FeSi films (∼3nm in thickness) grown on Si(111) by solid-phase epitaxy indicating the monoclinic symmetry to fit better the film structure as compared to the cubic symmetry, as well as by resistivity versus temperature measurements within a wide temperature range (2–300 K) pointing out bad metal properties. The analysis of field and temperature dependences of the magnetic moment of ultrathin FeSi films shows the presence of a ferromagnetic-antiferromagnetic two-phase state. We also discuss how our findings of the new phase of FeSi can interpret its known experimental data on electronic, transport and optical properties without involving the metal–insulator transition and Kondo-like effects.

A Simple Synthesis and Microstructure Analysis of Human Peptide LL-37@Gold Nanoparticles (Known as LL-37@AuNPs) Conjugates as Antimicrobials and Substances for Wound Healing.

The basis of the present study is a straightforward method involving fewer chemical species for conjugating gold nanoparticles (AuNPs) with the antimicrobial peptide LL-37 designated as LL-37@AuNPs. Investigating the microstructure characteristics of the resulting materials and their potential as antibacterial and wound-healing substances are the main objectives of this study. Zeta (ζ) potential, Fourier transform infrared (FTIR), X-ray diffraction (XRD), field effect scanning electron microscopy (FE-SEM), energy dispersive X-ray diffraction (EDS), transmission electron microscopy (TEM), and UV-Vis spectrophotometry were used to analyze the physico-chemical properties of LL-37@AuNPs. The magnitude of LL-37's zeta potential and the LL-37@AuNPs show that the specimens are electrically stable and resistant to flocculation and coagulation. The surface plasmon resonance (RPS) of AuNPs, which is positioned at a wavelength of about 531 nm, was found to be unaffected by the presence of the LL-37 antimicrobial peptide. The FTIR data show the functional group characteristics of the LL-37@AuNPs vibration bands, and the XRD diffractogram confirms the formation of the LL-37@AuNPs conjugate nanocomposite. Based on FE-SEM and TEM data, the bulk of AuNPs were found to have a circular shape, with an average size of about 22.88 ± 8.21 nm. It was discovered that the LL-37@AuNPs had a good ability to inhibit S. aureus from growing. The wound-healing percentage reached 85% on day 12 of the trial, significantly greater than the results of the negative controls. LL-37@AuNPs(4) is the sample that had the highest percentage of wound healing between days 3 and 12. Moreover, sample LL-37@AuNPs(4) contains 0.45 µL of LL-37, whereas sample LL-37@AuNPs(2) contains 0.22 µL of LL-37. The faster wound-healing rate in LL-37@AuNPs(4) was believed to be due to a higher concentration of LL-37, which was able to stop S. aureus from developing while suppressing the inflammation surrounding the wound. The study's findings reveal that LL-37@AuNPs might be made using a straightforward process, making them a powerful antibacterial and therapeutic substance. However, before this discovery is applied in the field of medicine, a more thorough investigation is necessary.

Ag3PO4/g-C3N4/Zn3(PO4)2 catalyst with ternary heterostructure and Z-scheme/type Ⅱ dual pathway mechanism for high photocatalytic performance

A novel Ag3PO4/g-C3N4/Zn3(PO4)2 photocatalyst with ternary heterostructure and Z-scheme/type Ⅱ dual pathway mechanism was synthesized. Scanning electron microscopy and transmission electron microscopy data showed that Ag3PO4, Zn3(PO4)2, and g-C3N4 were in close contact, leading to the formation of the ternary heterojunction. Under simulated solar light irradiation, the Ag3PO4/g-C3N4/Zn3(PO4)2 photocatalyst efficiently degraded rhodamine B (RhB) and displayed much higher photocatalytic activity than pure Ag3PO4, g-C3N4, Zn3(PO4)2, and Ag3PO4/Zn3(PO4)2 composite, exhibiting a RhB photodegradation efficiency of ∼91.2 % within 60 min. The quenching effects of different scavengers and electron spin resonance (ESR) experiments demonstrated that reactive h+ and·O2− species played major roles in the photocatalytic reaction. It was elucidated that excellent photocatalytic activity could be ascribed to the Z-scheme/type Ⅱ dual carrier transfer pathways. Therefore, the formation of a ternary heterostructure system is an efficient method for separating charge carriers and retaining their redox capabilities.

The Effect of AlN Buffer Layer Morphology on the Structural Quality of a Semipolar GaN Layer Grown on a Si(001) Substrate, According to Transmission Electron Microscopy Data

The Effect of AlN Buffer Layer Morphology on the Structural Quality of a Semipolar GaN Layer Grown on a Si(001) Substrate, According to Transmission Electron Microscopy Data

AimSeg: A machine-learning-aided tool for axon, inner tongue and myelin segmentation.

Electron microscopy (EM) images of axons and their ensheathing myelin from both the central and peripheral nervous system are used for assessing myelin formation, degeneration (demyelination) and regeneration (remyelination). The g-ratio is the gold standard measure of assessing myelin thickness and quality, and traditionally is determined from measurements made manually from EM images-a time-consuming endeavour with limited reproducibility. These measurements have also historically neglected the innermost uncompacted myelin sheath, known as the inner tongue. Nonetheless, the inner tongue has been shown to be important for myelin growth and some studies have reported that certain conditions can elicit its enlargement. Ignoring this fact may bias the standard g-ratio analysis, whereas quantifying the uncompacted myelin has the potential to provide novel insights in the myelin field. In this regard, we have developed AimSeg, a bioimage analysis tool for axon, inner tongue and myelin segmentation. Aided by machine learning classifiers trained on transmission EM (TEM) images of tissue undergoing remyelination, AimSeg can be used either as an automated workflow or as a user-assisted segmentation tool. Validation results on TEM data from both healthy and remyelinating samples show good performance in segmenting all three fibre components, with the assisted segmentation showing the potential for further improvement with minimal user intervention. This results in a considerable reduction in time for analysis compared with manual annotation. AimSeg could also be used to build larger, high quality ground truth datasets to train novel deep learning models. Implemented in Fiji, AimSeg can use machine learning classifiers trained in ilastik. This, combined with a user-friendly interface and the ability to quantify uncompacted myelin, makes AimSeg a unique tool to assess myelin growth.

Description of four new filamentous cyanobacterial taxa from freshwater habitats in the Azores Archipelago.

Simple filamentous cyanobacteria comprise a diverse and polyphyletic group of species, primarily in the orders Leptolyngbyales and Oscillatoriales, that need more sampling to improve their taxonomy. Oceanic islands, such as the Azores archipelago, present unique habitats and biogeographic conditions that harbor an unknown range of diversity of microorganisms. Filamentous cyanobacteria isolated from aquatic habitats in the Azores and maintained in the BACA culture collection were described using morphology, both light and transmission electron microscopy, ecology, and genetic data of the 16S rRNA gene sequences and 16S-23S Internal Transcribed Spacer (ITS) rRNA region secondary structure. Our analyses revealed two new monophyletic genera: Tumidithrix elongata gen. sp. nov. (Pseudanabaenaceae) and Radiculonema aquaticum gen. sp. nov. (Leptolyngbyaceae). In addition, two new species Leptodesmis lacustris sp. nov. (Leptolyngbyaceae) and Pycnacronema lacustrum sp. nov. (Wilmottiaceae) are reported as the first aquatic species for these genera. The description of these new taxa and the genetic study of an isolate of Leptodesmis alaskaensis from the Azores followed the polyphasic approach, identifying diacritical features. Our results reinforce the need for taxonomic studies on cyanobacteria from less-studied habits and geographic regions, which have a potential for new taxa description.

Green adeptness in synthesis of non-toxic copper and cobalt oxide nanocomposites with multifaceted bioactivities

BackgroundIn the present era, we are facing different health problems mainly concerning with drug resistance in microorganisms as well as in cancer cells. In addition, we are also facing the problems of controlling oxidative stress and insect originated diseases like dengue, malaria, chikungunya, etc. originated from mosquitoes. In this investigation, we unfurled the potential of Achatina fulica mucus in green synthesis of mucus mediated copper oxide bio-nanocomposites (SM-CuONC) and cobalt oxide bio-nanocomposites (SM-Co3O4NC). Herein we carried out the physico-chemical characterization like UV–Vis spectra, X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission electron microscopy (TEM), Energy Dispersive X-ray Analysis (EDAX) and X-ray photoelectron spectroscopy (XPS) of as synthesized bio-nanocomposites. Both the bio-nanocomposites were tested for their potential as antimicrobial activity using well diffusion assay, anticancer activity by MTT assay, antioxidant activity by phosphomolybdenum assay and mosquito larvicidal activity.ResultsThe results of this study revealed that, SM-CuONC and SM-Co3O4NC were synthesized successfully using A. fulica mucus. The FESEM and TEM data reveal the formation of nanoparticles with quasi-spherical morphology and average particle size of ~ 18 nm for both nanocomposites. The EDAX peak confirms the presence of elemental copper and cobalt in the analyzed samples. The X-ray diffraction analysis confirmed the crystalline nature of the CuO and Co3O4. The result of anti microbial study exhibited that, SM-CuONC showed maximum antimicrobial activity against Escherichia coli NCIM 2065 and Aspergillus fumigatus NCIM 902 which were noted as 2.36 ± 0.31 and 2.36 ± 0.59 cm resp. at 60 µg/well concentration. The result of anticancer activity for SM-CuONC was exhibited as, 68.66 ± 3.72, 62.66 ± 3.61 and 71.00 ± 2.36 percent kill, while SM-Co3O4NC exhibited 61.00 ± 3.57, 72.66 ± 4.50 and 71.66 ± 4.22 percent kill against Human colon cancer (HCT-15), Cervical cancer (HeLa), and Breast cancer (MDA-MB-231) cell lines, respectively, at 20 µg/well concentration. Both the nanocomposites also exhibited better antioxidant activity. Total antioxidant activity for SM-CuONC at 50 µg/ml concentration was found to be highest as 55.33 ± 3.72 while that of SM-Co3O4Ns was 52.00 ± 3.22 mM of ascorbic acid/µg respectively. Both bio-nanocomposites also exhibited 100% mosquito larvicidal activity at concentration ranging from 40 to 50 mg/l. During cytotoxicity study it is noted that at 5 µg/well concentration, SM-CuO and SM-Co3O4NCs suspension showed more than 97% viability of normal (L929) cell lines. We also studied phytotoxicity of both bio-nanocomposites on Triticum aestivum. In this study, 100% seed germination was observed when seeds are treated with SM-CuONC and SM-Co3O4NC at 500 mg/l and 250 mg/l concentration respectively.ConclusionsThis study concludes that in future as synthesized SM-CuONC and SM-Co3O4NC can be used in pharmaceutical, health care system for betterment and welfare of human life as both bio-nanocomposites exhibits better antimicrobial, anticancer, antioxidant and mosquito larvicidal potential.

Design of Magnetic Fe3O4/CeO2 "Core/Shell"-Like Nanocomposites with Pronounced Antiamyloidogenic and Antioxidant Bioactivity.

"Core/shell" nanocomposites based on magnetic magnetite (Fe3O4) and redox-active cerium dioxide (CeO2) nanoparticles (NPs) are promising in the field of biomedical interests because they can combine the ability of magnetic NPs to heat up in an alternating magnetic field (AMF) with the pronounced antioxidant activity of CeO2 NPs. Thus, this report is devoted to Fe3O4/CeO2 nanocomposites (NCPs) synthesized by precipitation of the computed amount of "CeO2-shell" on the surface of prefabricated Fe3O4 NPs. The X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy data validated the formation of Fe3O4/CeO2 "core/shell"-like NCPs, in which ultrafine CeO2 NPs with an average size of approximately 3-3.5 nm neatly surround Fe3O4 NPs. The presence of a CeO2 "shell" significantly increased the stability of Fe3O4/CeO2 NCPs in aqueous suspensions: Fe3O4/CeO2 NCPs with "shell thicknesses" of 5 and 7 nm formed highly stable magnetic fluids with ζ-potential values of >+30 mV. The magnetization values of Fe3O4/CeO2 NCPs decreased with a growing CeO2 "shell" around the magnetic NPs; however, the resulting composites retained the ability to heat efficiently in an AMF. The presence of a CeO2 "shell" generates a possibility to precisely regulate tuning of the maximum heating temperature of magnetic NCPs in the 42-50 °C range and stabilize it after a certain time of exposure to an AMF by changing the thickness of the "CeO2-shell". A great improvement was observed in both antioxidant and antiamyloidogenic activities. It was found that inhibition of insulin amyloid formation, expressed in IC50 concentration, using NCPs with a "shell thickness" of 7 nm was approximately 10 times lower compared to that of pure CeO2. For these NCPs, more than 2 times higher superoxide dismutase-like activity was observed. The coupling of both Fe3O4 and CeO2 results in higher bioactivity than either of them individually, probably due to a synergistic catalytic mechanism.

Surface Engineering of Multi-Walled Carbon Nanotubes via Ion-Beam Doping: Pyridinic and Pyrrolic Nitrogen Defect Formation

In this study, we present an innovative ion-beam doping technique for the controlled modification of the near-surface region of multi-walled carbon nanotubes (MWCNTs) aimed at creating pyridinic and pyrrolic nitrogen defects in their walls. This method involves the irradiation of MWCNTs with nitrogen ions using a high-dose ion implanter, resulting in the incorporation of nitrogen atoms into the nanotube structure. The structural and chemical changes induced by the ion-beam treatment were thoroughly characterized. Scanning electron microscopy (SEM) analysis revealed subtle changes in nanotube morphology, while X-ray diffraction (XRD) measurements exhibited altered peak intensities and a shift in the (002) reflection peak, indicating structural modifications, which correlates with transmission electron microscopy (TEM) data. X-ray photoelectron spectroscopy (XPS) analysis confirmed the successful embedding of nitrogen, mainly in pyridinic and pyrrolic configurations, as evidenced by the presence of corresponding lines in the N1s spectrum. Our findings demonstrate the feasibility of precisely engineering nitrogen defects in MWCNTs using the ion-beam doping technique. This approach is expected to be promising for the use of carbon nanotubes surface-functionalized with nitrogen atoms in the development of new devices for electronics, electrochemistry, catalysis, etc.

Characterizing the Ligand Shell Morphology of PEG-Coated ZnO Nanocrystals Using FRET Spectroscopy.

Poly(ethylene glycol) (PEG) ligands can inhibit proteins and other biomolecules from adhering to underlying surfaces, making them excellent surface ligands for nanocrystal (NC)-based drug carriers. Quantifying the PEG ligand shell morphology is important because its structure determines the permeability of biomolecules through the shell to the NC surface. However, few in situ analytical tools can reveal whether the PEG ligands form either an impenetrable barrier or a porous coating surrounding the NC. Here, we present a Förster resonance energy transfer (FRET) spectroscopy-based approach that can assess the permeability of molecules through PEG-coated ZnO NCs. In this approach, ZnO NCs serve as FRET donors, and freely diffusing molecules in the bulk solution are FRET acceptors. We synthesized a series of variable chain length PEG-silane-coated ZnO NCs such that the longest chain length ligands far exceed the Förster radius (R0), where the energy transfer (EnT) efficiency is 50%. We quantified the EnT efficiency as a function of the ligand chain length using time-resolved photoluminescence lifetime (TRPL) spectroscopy within the framework of FRET theory. Unexpectedly, the longest PEG-silane ligand showed equivalent EnT efficiency as that of bare, hydroxyl-passivated ZnO NCs. These results indicate that the "rigid shell" model fails and the PEG ligand shell morphology is more likely porous or in a patchy "mushroom state", consistent with transmission electron microscopy data. While the spectroscopic measurements and data analysis procedures discussed herein cannot directly visualize the ligand shell morphology in real space, the in situ spectroscopy approach can provide researchers with valuable information regarding the permeability of species through the ligand shell under practical biological conditions.