Transmission Electron Microscopy Studies Research Articles

Synthesis and multifunctional characterizations of Gd2 O3 and Sm2 O3 modified ZnO nanoparticles

In the present communication multifunctional characterizations suitable for spintronics and memory storage devices are described. Double doped (Gd3+, Sm3+) ZnO nanoparticles are prepared from Sol-Gel method using poly vinyl alcohol (PVA) as chelating agent. The as prepared powders are annealed at 500 °C–1000 °C with a step size of 100 °C. The genesis of single phase hexagonal wurtzite structure, morphological and topographical changes, optical, magnetic and mechanical properties were studied with XRD (X-ray diffraction), SEM (scanning electron microscopy), TEM (transmission electron microscopy), EDS (energy dispersive spectroscopy), UV- DRS (ultraviolet diffuse reflective spectroscopy), PL (photoluminescence), VSM (vibrating sample magnetometer) and pin on disc tribometer. XRD study untangled the crystallite size and found to be in the range23-50nm. Polycrystalline nanoparticles of spherical geometry with induced porosity is observed from SEM study. The particle size associated with the samples annealed at 500 °C and 900 °C is 24 nm and 27 nm respectively from TEM study. Analyzed the proximity of functional groups, molecular vibrations in the range of 400-4000 cm−1 employing FTIR (Fourier transform infrared spectroscopy). EDS results revealed the stoichiometry of the produced samples. The pronounced optoelectronic applications of Zn1-x Gdx Smx O (ZGS) can be attributed to the large band gap (3.50–3.02 eV) associated with the materials with rise in annealing temperature. The room temperature ferromagnetism was evidenced with double doped ZnO nanomaterials. The wear coefficient, and friction coefficient were evaluated using pin-on-disc tribometer. The utility of materials as solid state lubricants was confiscated from the range of frictional coefficient values (0.067–0.893).

Crystal structures of two new high-pressure oxynitrides with composition SnGe4N4O4, from single-crystal electron diffraction.

SnGe4N4O4 was synthesized at high pressure (16 and 20 GPa) and high temperature (1200 and 1500°C) in a large-volume press. Powder X-ray diffraction experiments using synchrotron radiation indicate that the derived samples are mixtures of known and unknown phases. However, the powder X-ray diffraction patterns are not sufficient for structural characterization. Transmission electron microscopy studies reveal crystals of several hundreds of nanometres in size with different chemical composition. Among them, crystals of a previously unknown phase with stoichiometry SnGe4N4O4 were detected and investigated using automated diffraction tomography (ADT), a three-dimensional electron diffraction method. Via ADT, the crystal structure could be determined from single nanocrystals in space group P63mc, exhibiting a nolanite-type structure. This was confirmed by density functional theory calculations and atomic resolution scanning transmission electron microscopy images. In one of the syntheses runs a rhombohedral 6R polytype of SnGe4N4O4 could be found together with the nolanite-type SnGe4N4O4. The structure of this polymorph was solved as well using ADT.

Biochemical and immunomodulatory insights of extracellular matrix from decellularized human whole cervix: recellularization and in vivo ECM remodeling interplay

Extracellular matrix (ECM) rich whole organ bio-scaffolds, preserving structural integrity and essential growth factors, has potential towards regeneration and reconstruction. Women with cervical anomalies or trauma can benefit from clinical cervicovaginal repair using constructs rich in site specific ECM. In this study, complete human cervix decellularization was achieved using a modified perfusion-based stir bench top decellularization method. This was followed by physico-chemical processes including perfusion of ionic agents, enzymatic treatment and washing using detergent solutions for a duration of 10–12 d. Histopathological analysis, as well as DNA quantification confirmed the efficacy of the decellularization process. Tissue ultrastructure integrity was preserved and the same was validated via scanning electron microscopy and transmission electron microscopy studies. Biochemical analysis and structural characterizations like Fourier transform infrared, Raman spectroscopy of decellularized tissues demonstrated preservation of important proteins, crucial growth factors, collagen, and glycosaminoglycans. In vitro studies, using THP-1 and human umbilical vein endothelial cell (HUVEC) cells, demonstrated macrophage polarization from M1 to M2 and vascular functional genes enhancement, respectively, when treated with decellularized human cervical matrix (DHCp). Crosslinked DHC scaffolds were recellularized with site specific human cervical epithelial cells and HUVEC, showing non-cytotoxic cell viability and enhanced proliferation. Furthermore, DHC scaffolds showed immunomodulatory effects in vivo on small rodent model via upregulation of M2 macrophage genes as compared to decellularized rat cervix matrix scaffolds (DRC). DHC scaffolds underwent neo-vascularization followed by ECM remodeling with enhanced tissue integration.

SDPR expression in human trabecular meshwork and its potential role in racial disparities of glaucoma

In order to identify how differential gene expression in the trabecular meshwork (TM) contributes to racial disparities of caveolar protein expression, TM dysfunction and development of primary open angle glaucoma (POAG), RNA sequencing was performed to compare TM tissue obtained from White and Black POAG surgical (trabeculectomy) specimens. Healthy donor TM tissue from White and Black donors was analyzed by PCR, qPCR, immunohistochemistry staining, and Western blot to evaluate SDPR (serum deprivation protein response; Cavin 2) and CAV1/CAV2 (Caveolin 1/Caveolin 2). Standard transmission electron microscopy (TEM) and immunogold labeled studies were performed. RNA sequencing demonstrated reduced SDPR expression in TM from Black vs White POAG patients’ surgical specimens, with no significant expression differences in other caveolae-associated genes, confirmed by qPCR analysis. No racial differences in SDPR gene expression were noted in healthy donor tissue by PCR analysis, but there was greater expression as compared to specimens from patients with glaucoma. Analysis of SDPR protein expression confirmed specific expression in the TM regions, but not in adjacent tissues. TEM studies of TM specimens from healthy donors did not demonstrate any racial differences in caveolar morphology, but a significant reduction of caveolae with normal morphology and immuno-gold staining of SDPR were noted in glaucomatous TM as compared to TM from healthy donors. Linkage of SDPR expression levels in TM, POAG development, and caveolar ultrastructural morphology may provide the basis for a novel pathway of exploration of the pathologic mechanisms of glaucoma. Differential gene expression of SDPR in TM from Black vs White subjects with glaucoma may further our understanding of the important public health implications of the racial disparities of this blinding disease.

Mitochondrial involvement in the metabolic defects evoked by hepatocyte-specific BBSome deficiency

The BBSome, a protein complex of 8 Bardet-Biedl syndrome (BBS) proteins including BBS1, has emerged as an important regulator of metabolic function. BBSome deficient human and mice display several metabolic features including obesity and type 2 diabetes. Here, we show that mice lacking the BBSome specifically in liver which were generated by crossing the Bbs1fl/fl mice with liver-specific (albumin) AlbCre mice exhibit significantly higher lipid droplets in liver, by Oil Red-O staining, and in primary cultured hepatocytes (5.7%±0.4% vs 2.4%±0.6%, control), and by Transmission electron microscope (TEM). AlbCre/Bbs1flox also have elevated fasting glucose (169± 14 vs 136±8 mg/dL, p<0.05) and impaired insulin sensitivity. In addition, insulin-induced activation of AKT was significantly decreased in the liver (2.6±0.07 vs 6.6± 0.34 AU, p<0.05), but not in white adipose tissue and skeletal muscle, of AlbCre/Bbs1flox mice. Using immunohistochemistry, we found that insulin receptor level in plasma membrane was decreased by 24.2±6.8% in primary cultured hepatocytes derived from AlbCre/Bbs1flox mice which explains the insulin resistance. Our previous work implicating the BBSome in the regulation of mitochondria led us to hypothesize that mitochondria dysfunction contributes to the development of metabolic defects in AlbCre/Bbs1flox mice. TEM studies revealed that mitochondria were significantly larger and longer in hepatocytes of AlbCre/Bbs1flox mice than controls. This was associated with decreased levels of Dynamin-related protein 1 (DRP1), which critically regulates mitochondrial function through fission. Next, we asked whether the mitochondrial defects may explain the insulin receptor mistraffcking in BBSome deficient hepatocytes. To test this, hepatocytes were infected with feline immunodeficiency virus that express an active mutant form of DRP1 (FIV-DRP1S637A). Interestingly, insulin receptor localization in the plasma membrane was significantly higher in hepatocytes of Bbs1fl/fl/AlbCre­ mice infected with FIV-DRP1S637A pointing to mitochondrial defects as the underlying cause of insulin receptor mislocalization induced by hepatic BBSome deficiency. Taken together, these findings demonstrate that BBSome regulation of metabolic function involve mitochondria. NIH and VA. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Influences of morphology, cation distribution and surface spin canting on magnetic and hyperfine properties of mechanically activated and subsequently heat treated nanosized Co0.8Zn0.2Fe2O4 exhibiting excellent catalytic activity

Herein, we have shown that the particle size, cation redistribution, interparticle interactions, surface spin disorder and strain induced anisotropy play a pivotal role in shaping the magnetic and hyperfine properties of nanosized Co0.8Zn0.2Fe2O4 samples prepared by coprecipitation method followed by high energy ball milling and subsequent thermal treatment. Three samples with different particle size viz., 23 nm (CZ1), 34 nm (CZ2) and 42 nm (CZ3) are characterized by powder x-ray diffraction, transmission electron microscopy and energy dispersive x-ray spectroscopy studies. The samples are well-crystalline, single-phase spinel with appropriate stoichiometry, assorted size and shape. All three samples are magnetically ordered at 300 K with MSAT and HC values 75.22, 81.07, 82.89 emu g−1, respectively, and 530, 460, 420 Oe, respectively. The values of coercivity at 10 K are remarkably high. Cation distribution of CZ1, CZ2 and CZ3 as estimated by taking into account the results of infield Mössbauer spectroscopic study and powder x-ray diffraction in conjugation are: (Co0.272+Zn0.202+Fe0.533+)A[Co0.532+Fe1.473+]BO4 (core region of CZ1), (Co0.432+Zn0.202+Fe0.373+)A,[Co0.372+Fe1.633+]BO4 (shell region of CZ1), (Co0.282+Zn0.202+Fe0.523+)A[Co0.522+Fe1.483+]BO4 and (Co0.242+Zn0.202+Fe0.563+)A[Co0.562+Fe1.443+]BO4, respectively. Further, this result has been validated theoretically. Owing to the core-shell structure (ferrimagnetically ordered core surrounded by a disordered shell), sample CZ1 having particle size below calculated critical diameter (∼ 27 nm) exhibits exchange bias effect. All three samples display excellent catalytic activity in the multicomponent reaction for the synthesis of coumarin-3-carboxamide. CZ1 shows best catalytic activity owing to its high surface to volume ratio.

Berberine HCl and diacerein loaded dual delivery transferosomes: Formulation and optimization using Box-Behnken design.

Berberine is a poorly water-soluble alkaloid compound showing significant anti-inflammatory characteristics. It reduces the levels of pro-inflammatory and inflammatory cytokines, including tumour necrosis factor (TNF-α, IFN-γ) and interleukin (IL-23, IL-12, and IL-23). Diacerein significantly reduces the splenomegaly associated with psoriasis. It downregulates the production of TNF-α and IL-12. This study reported the development of transferosomes containing berberine HCl and diacerein using a film hydration method followed by optimization using a Box-Behnken design. Sodium deoxycholate was used as an edge activator. The impact of independent variables (amount of phosphatidylcholine, amount of edge activator, and sonication cycles) on dependent variables (particle size and entrapment efficiency) was examined. The optimized formulation was characterized for polydispersity index, vesicle size, entrapment efficiency, ζ potential, spectral analysis like Fourier transform infrared, thermal analysis, X-ray diffraction, deformability, transmission electron microscopy, antioxidant assay, in-vitro release, and ex-vivo skin permeation studies. The optimized formulation had a particle size of 110.90±2.8 nm with high entrapment efficiency (89.50±1.5 of berberine HCl and 91.23±1.8 of diacerein). Deformability, polydispersity index, ζ potential, and antioxidant activity of the optimized formulation were 2.44, 0.296, -13.3, and 38.36 %, respectively. Optimized transferosomes exhibited 82.093±0.81 % and 85.02±3.81 % release of berberine HCl and diacerein after 24 h of dissolution study. The transdermal flux of optimized formulation was 0.0224 μg cm-2 h-1 (2.24 cm h-1 permeation coefficient) and 0.0462 μg cm-2 h-1 (4.62 cm h-1 permeation coefficient), respectively, for berberine HCl and diacerein. Raman analysis of treated pig skin confirmed that the transferosomes can permeate the skin. No change in the skin condition or irritation was observed in BALB/c mice. Formulation stored at 4 and 25±2 °C / 60±5 % relative humidity was stable for 3 months. Thus, the results demonstrated successful optimization of the transferosomes for the efficient topical delivery of berberine HCl and diacerein in the effective management of psoriasis.

Sustainable hybrid green nanofiller based on cellulose nanofiber for enhancing the properties of epoxy resin

Herein, a novel hybrid nano filler (CNF/cloisite 30B) for epoxy was designed and developed from cellulose nanofiber (CNF) and montmorillonite clay (cloisite 30B). The hybrid nanofiller has a morphology of exfoliated clay layers inside fibrous network of CNF as evident by transmission electron microscopy (TEM) and X-ray diffraction (XRD) studies. The crystallinity index of hybrid nanofiller was calculated as 17% from Segal equation. Upon incorporation of hybrid nanofiller, thermal, mechanical and flame-retardant properties of the epoxy was simultaneously increased. A surge in the impact strength (101%) was observed for epoxy/0.5 hybrid nanocomposites. Fracture toughness of the epoxy increases with the addition of hybrid nanofiller, 0.5 phr loading shows the maximum fracture toughness value. Besides this, inclusion of hybrid nanofiller makes the fracture surface of epoxy rougher as confirmed by field emission scanning electron microscopy (FESEM). A significant improvement in the glass transition temperature (Tg) was observed for the fabricated epoxy/hybrid nanocomposites. Compared to pristine epoxy, about 16% and 10% improvement in Tg was observed for 0.5 phr and 1.0 phr CNF/cloisite30 B hybrid loading, respectively. Well-dispersed hybrid nanofiller in the epoxy matrix and the resulting filler matrix interaction restrict the chain mobility by forming several constrained regions in the nanocomposites, which in turn enhances the glass transition temperature of the hybrid nanocomposites. Hybrid nanocomposites exhibited remarkable flame retardancy due to the formation of thick char layer and the reduction in the total heat released (THR) was 34% and 20% compared to neat epoxy resin. The current work ensures that the developed hybrid green filler can be a potential, low cost, and eco-friendly reinforcing agent for polymers.

Green synthesis of Nyctanthes arbor-tristis flower-decorated gold nanoparticles: Sustainable approaches for enhancing antimicrobial and supercapacitor performance

The physiochemical and electrochemical characteristics of gold nanoparticles (AuNPs) produced by phytosynthesis technique at varying concentrations of Nyctanthes arbor-tristis flower (NAF) are presented in this study. The final porous carbon decorated AuNPs have possible applications in antibacterial research as well as energy storage field. Transmission electron microscopy (TEM) studies revealed tiny spherical shaped nanoparticles, and UV–visible spectroscopy showed size-dependent optical properties. Significant antibacterial efficacy against Pseudomonas aeruginosa was shown by the NAF-derived AuNPs. A symmetric supercapacitor with 64 F g−1 specific capacitance at 1 A g−1 and 97% cycling stability after 5000 charge-discharge cycles was produced using the as-synthesized electrode. This study provides a sustainable method for producing multifunctional nanomaterials by highlighting the potential of NAF-derived AuNPs for dual applications in the antibacterial and supercapacitor areas.

Tau-borides (Mnx{Ru,Os,Ir}1-x)23B6: X-ray single crystal and TEM data, physical properties

Investigation (electron microprobe and X-ray powder and single crystal diffraction analyses) of the phase relations in the Mn-rich corner (> 45 at% Mn) of the systems Mn-{Ru,Os,Ir}-B, prompted in all three systems a ternary compound with formula (Mnx{Ru,Os,Ir}1-x)23B6. For the systems Mn-Ru-B, Mn-Ir-B phase equilibria have been determined at 950°C (Ru), 900°C (Ir) revealing in both cases a small homogeneity region at constant B-content (Mn1-xRux)23B6 (0.29 < x < 0.37); (Mn1-xOsx)23B6 (0.33 < x < 0.37), as well as (Mn1-xIrx)23B6 (0.29 < x < 0.34). The crystal structure of the three compounds was determined from single crystal and X-ray powder intensity data analyses to be isotypic with the Cr23B6-type (so-called tau-phase, space group Fm3¯m, No. 225). In all cases Mn atoms fully occupy the 4a site (0,0,0) at the origin of the unit cell. For the 8c site (¼,¼,¼) we observed a random distribution of Mn1-x(PM)x with decreasing PM content (PM stands for a platinum group metal atom) going from Ru to Os and Ir, where Mn atoms fully occupy 8c. Whereas the remaining sites (48h, 32f) show various ratios of the two metal species, boron atoms fully occupy the centers (24e site) of the Archimedean metal atom antiprisms. A transmission electron microscopic study confirms the absence of superstructures related to these metal atom disorder, thus Mn and PM atoms randomly share their sites. The latter is well reflected in the behavior of the electrical resistivity of these compounds, which is dominated by disorder scattering. For (Mn0.6{Ru,Os}0.4)23B6, temperature dependent dc magnetization studies reveal distinct antiferromagnetic-like anomalies at TN ≅ 72 K and 114 K, respectively. Low field dc and ac magnetic susceptibility data of (Mn0.7Ir0.3)23B6 display a distinct ferromagnetic-like transition at TC = 280 K, consistent with a pronounced specific heat anomaly and a rather continuous temperature dependent evolution of magnetic anisotropy effects. Mechanical properties (hardness) characterize the tau phases among rather hard and brittle intermetallics (about 5–6 GPa).

Ultrastructural, molecular and haemato-immunological changes: Multifaceted toxicological effects of microcystin-LR in rohu, Labeo rohita

No water body is resilient to afflicts of algal bloom, if goes unmanaged. With the increasing trend of intensification, eutrophication and climate change, Labeo rohita (rohu) is highly anticipated to suffer from the deleterious effects of bloom and eventually its toxins. A comprehensive study was conducted to understand the toxicopathological effects of microcystin-LR (MC-LR) in rohu following intraperitoneal injection of 96 h-LD50 dose i.e., 713 μg kg−1. Substantial changes in micro- and ultrastructural level were evident in histopathology and transmission electron microscope (TEM) study. The haematological, biochemical, cellular and humoral innate immune biomarkers were significantly altered (p < 0.05) in MC-LR treated fish. The mRNA transcript levels of IL-1β, IL-10, IgM and IgZ in liver and kidney tissues were significantly up-regulated in 12 hpi and declined in 96 hpi MC-LR exposed fish. The relative mRNA expression of caspase 9 in the liver and kidney indicates mitochondrial-mediated apoptosis which was strongly supported by TEM study. In a nutshell, our study illustrates for the first time MC-LR induced toxicological implications in rohu displaying immunosuppression, enhanced oxidative stress, pathophysiology, modulation in mRNA transcription, genotoxicity, structural and ultrastructural alterations signifying it as a vulnerable species for MC-LR intoxication.

Oligomerization states of the Mycobacterium tuberculosis RNA polymerase core and holoenzymes.

During the past few decades, a wealth of knowledge has been made available for the transcription machinery in bacteria from the structural, functional and mechanistic point of view. However, comparatively little is known about the homooligomerization of the multisubunit M. tuberculosis RNA polymerase (RNAP) enzyme and its functional relevance. While E. coli RNAP has been extensively studied, many aspects of RNAP of the deadly pathogenic M. tuberculosis are still unclear. We used biophysical and biochemical methods to study the oligomerization states of the core and holoenzymes of M. tuberculosis RNAP. By size exclusion chromatography and negative staining Transmission Electron Microscopy (TEM) studies and quantitative analysis of the TEM images, we demonstrate that the in vivo reconstituted RNAP core enzyme (α2ββ'ω) can also exist as dimers in vitro. Using similar methods, we also show that the holoenzyme (core + σA) does not dimerize in vitro and exist mostly as monomers. It is tempting to suggest that the oligomeric changes that we see in presence of σA factor might have functional relevance in the cellular process. Although reported previously in E. coli, to our knowledge we report here for the first time the study of oligomeric nature of M. tuberculosis RNAP in presence and absence of σA factor.

OSW-1 triggers necroptosis in colorectal cancer cells through the RIPK1/RIPK3/MLKL signaling pathway facilitated by the RIPK1-p62/SQSTM1 complex.

Necroptosis has emerged as a novel molecular pathway that can be targeted by chemotherapy agents in the treatment of cancer. OSW-1, which is derived from the bulbs of Ornithogalum saundersiae Baker, exerts a wide range of pharmacological effects. To explore whether OSW-1 can induce necroptosis in colorectal cancer (CRC) cells, thereby expanding its range of clinical applications. We performed a sequence of functional experiments, including Cell Counting Kit-8 assays and flow cytometry analysis, to assess the inhibitory effect of OSW-1 on CRC cells. We utilized quantitative proteomics, employing tandem mass tag labeling combined with liquid chromatography-tandem mass spectrometry, to analyze changes in protein expression. Subsequent bioinformatic analysis was conducted to elucidate the biological processes associated with the identified proteins. Transmission electron microscopy (TEM) and immunofluorescence studies were also performed to examine the effects of OSW-1 on necroptosis. Finally, western blotting, siRNA experiments, and immunoprecipitation were employed to evaluate protein interactions within CRC cells. The results revealed that OSW-1 exerted a strong inhibitory effect on CRC cells, and this effect was accompanied by a necroptosis-like morphology that was observable via TEM. OSW-1 was shown to trigger necroptosis via activation of the RIPK1/RIPK3/MLKL pathway. Furthermore, the accumulation of p62/SQSTM1 was shown to mediate OSW-1-induced necroptosis through its interaction with RIPK1. We propose that OSW-1 can induce necroptosis through the RIPK1/RIPK3/MLKL signaling pathway, and that this effect is mediated by the RIPK1-p62/SQSTM1 complex, in CRC cells. These results provide a theoretical foundation for the use of OSW-1 in the clinical treatment of CRC.

Facile combustion-synthesis, structural, morphological, vibrational, photoluminescence, dielectric, and electrical properties of ZnFe2O4 nanostructures: an effect of citric acid concentrations

In the current report, we have facilely synthesized the ZnFe2O4 nanoparticles (ZFO NPs) using the flash combustion route at 600 °C with various concentrations of citric acid (CA). The structural, vibrational, and elemental/homogeneity analyses through XRD, Raman, and energy dispersive X-ray spectroscopy/Scanning electron microscopy e-mapping confirmed the cubic phase and composition of synthesized ZFO NPs. The crystallite size was estimated using Scherrer and Williamson-Hall plot methods and noticed to be reduced with an increasing amount of CA in ZFO and found between 15 and 30 nm, which was also supported by scanning electron and transmission electron microscopic studies. X-ray photoelectron spectroscopy analysis confirmed the synthesis of ZnFe2O4. The ZFO NPs were excited at 417 nm to record the luminescence spectra and found the emission peaks at 456±2, 530±3, and 625±5 nm. The dielectric constant was found to be between 147 and 165 with low loss values, and the electrical conductivity was found to be enhanced with CA content in ZFO NPs. The magnetic properties were also studied at 300 K and disused. These outcomes indicate that the properties of ZFO NPs have been greatly influenced by crystallite/grain size variation, which resulted from different CA concentration-assisted synthesis of ZFO and possess the potential for optoelectronic and energy storage devices.

Evaluation of Interface and Residual Strain of NiTi Layer Deposited on NiTiX Substrate by Laser Powder Bed Fusion

This study investigates the microstructure and properties of functionally graded NiTi alloy bilayers. The NiTi layer is printed by laser powder bed fusion on a NiTiX (where X is Hf or Cu) substrate prepared by vacuum arc remelting. Specimens produced with different thicknesses of layers, but constant thickness ratio, are examined by optical and scanning electron microscopy prior to and postannealing process at 1000 °C for 16 h. Scanning electron microscopy– energy‐dispersive X‐ray spectroscopy and transmission electron microscopy studies reveal the presence of Ti2Ni and Ni4Ti3 precipitates in the as‐printed NiTi/NiTiCu samples and Ti2Ni type precipitates in as‐printed NiTi/NiTiHf. Digital image correlation quantifies residual strain in the as‐printed bilayer and enables strain relief to be monitored during heating. It has been shown that microcracks occurring along interfacial zones during the laser powder bed fusion are diminished after annealing heat treatment. The microcrack closure occurs by diffusion of third elements to the open microcracks, leading to precipitation and accumulation of third elements in the interfaces. Eventually, the as‐printed NiTi/NiTiCu sample displays two‐way shape memory effects with about 24.5% shape recovery. This work enhances understanding of controlling fabrication to yield tailored properties in additively manufactured functionally graded NiTi‐based materials.

Understanding the sigmoidal primary creep behaviour in a multi-component solid-solution Co-base alloy between 700 – 850 °C

This investigation was motivated by the lack of understanding of the role of solid solution strengthening and substructure evolution during the creep of multi-component alloys. Thus, we studied the tensile creep behaviour of a multi-component solid-solution Co-base alloy (Co41-Ni23-Cr26-W4.7-Fe2-Mn1-C0.5) at 650 – 900 °C and stress (σApplied) range: 80 – 400 MPa. Uncommon sigmoidal primary creep (SPC) was witnessed at 700–850 °C and in the intermediate stress range. The stress exponent (∼5 – 7) and activation energy (∼270 kJ/mol ≈ Qlattice) suggest that dislocation creep controls the creep rate. Transmission electron microscopy (TEM) studies revealed substructural evolution with creep strain. At 750 °C and 160 MPa, at creep strain (ε) = 0.25 %, multiple pinning points along the dislocation length were seen, and a thorough analysis confirmed them as jogs. Friction stress estimation from dislocation curvature from multiple TEM micrographs revealed that effective stress on dislocations is high (>0.6σApplied) while solid solution strengthening is nominal during creep. Overall analysis suggests that the creep rate in the multi-component alloy is recovery controlled while jogs' motion determines the SPC creep rate.

Bisphenol-F and Bisphenol-S (BPF and BPS) Impair the Stemness of Neural Stem Cells and Neuronal Fate Decision in the Hippocampus Leading to Cognitive Dysfunctions.

Neurogenesis occurs throughout life in the hippocampus of the brain, and many environmental toxicants inhibit neural stem cell (NSC) function and neuronal generation. Bisphenol-A (BPA), an endocrine disrupter used for surface coating of plastic products causes injury in the developing and adult brain; thus, many countries have banned its usage in plastic consumer products. BPA analogs/alternatives such as bisphenol-F (BPF) and bisphenol-S (BPS) may also cause neurotoxicity; however, their effects on neurogenesis are still not known. We studied the effects of BPF and BPS exposure from gestational day 6 to postnatal day 21 on neurogenesis. We found that exposure to non-cytotoxic concentrations of BPF and BPS significantly decreased the number/size of neurospheres, BrdU+ (proliferating NSC marker)and MAP-2+ (neuronal marker) cells and GFAP+ astrocytes in the hippocampus NSC culture, suggesting reduced NSC stemness and self-renewal and neuronal differentiation and increased gliogenesis. These analogs also reduced the number of BrdU/Sox-2+, BrdU/Dcx+, and BrdU/NeuN+ co-labeled cells in the hippocampus of the rat brain, suggesting decreased NSC proliferation and impaired maturation of newborn neurons. BPF and BPS treatment increases BrdU/cleaved caspase-3+ cells and Bax-2 and cleaved caspase protein levels, leading to increased apoptosis in hippocampal NSCs. Transmission electron microscopy studies suggest that BPF and BPS also caused degeneration of neuronal myelin sheath, altered mitochondrial morphology, and reduced number of synapses in the hippocampus leading to altered cognitive functions. These results suggest that BPF and BPS exposure decreased the NSC pool, inhibited neurogenesis, induced apoptosis of NSCs, caused myelin degeneration/synapse degeneration, and impaired learning and memory in rats.

Activity of pure flavonoid-based green silver nano particles against breast cancer: A combined experimental and computational investigation

Because of the wide range of applications in various industries, the development of novel nanomaterials is receiving more and more attention nowadays. A green route to synthesize one such versatile nanomaterial, silver nanoparticles (AgNPs) with a pure flavonoid, quercetin has been explored in this study. The reducing and capping mechanism of quercetin was examined using density functional theory (DFT). Dynamic light scattering (DLS), UV–vis spectra (UV–Vis), and Transmission Electron Microscopy (TEM) studies confirmed that the synthesized AgNPs are stable, monodispersed, spherical shaped with an average size of 16 nm. A molecular docking study has identified the epidermal growth factor receptor (EGFR) protein as a potential target for quercetin-capped AgNPs to fight against breast cancer. Molecular dynamics (MD) simulation has quantified the efficiency of quercetin-capped AgNPs over quercetin only in targeting breast cancer. These findings will be helpful in using quercetin-based AgNPs for drug discovery against breast cancer.

Evidence of Cationic Antiphase Disorder in Epitaxial Cu(In,Ga)S2 Grown on GaP/Si(001)

A transmission electron microscopy study of epitaxial Cu(In,Ga)S2 (CIGS) films coevaporated on GaP/Si(001), in either Cu‐rich or Cu‐poor conditions, is presented. The spatial distribution and the orientation of the different phases by means of electron diffraction are unveiled. From atomically resolved imaging of the CIGS film's atomic structure, it is concluded that different chalcopyrite domains, sharing cation antiphase symmetries of the cation sublattice, coexist in the films. At least three types of cation antiphase boundaries (CAPBs), which do or do not lead to a violation of the octet rule, depending on the propagation direction, are conceptualized. Even though it is observed that epitaxial CIGS is highly prone to cation antiphase disorder (CAPD), and it is found that the growth of CIGS in Cu‐rich conditions leads to a lower density of CAPBs, as compared to Cu‐poor growth conditions. This opens the question of the influence of CAPBs on CIGS electronic properties.

Ruddlesden-Popper Perovskite Nanocrystals as Interface Modification Layer for Efficient Perovskite Solar Cells.

Perovskite nanocrystals are advantageous for interfacial passivation of perovskite solar cells (PSCs), but the insulating long alkyl chain surface ligands impede the charge transfer, while the conventional ligand exchange would possibly introduce surface defects to the nanocrystals. In this work, we reported novel in situ modification of CsPbBr3 nanocrystals using a short chain conjugated molecule 2-methoxyphenylethylammonium iodide (2-MeO-PEAI) for interfacial passivation of PSCs. Transmission electron microscopy studies with atomic resolution unveil the transformation from cubic CsPbBr3 to Ruddlesden-Popper phase (RPP) nanocrystals due to halogen exchange. Synergic passivation by the RPP nanocrystals and 2-MeO-PEA+ has led to suppressed interface defects and enhanced charge carrier transport. Consequently, PSCs with in situ modified RPP nanocrystals achieved a champion power conversion efficiency of 24.39%, along with an improvement in stability. This work brings insights into the microstructural evolution of perovskite nanocrystals, providing a novel and feasible approach for interfacial passivation of PSCs.