TEM Data Research Articles

Spatiotemporal Changes in Vegetation Cover and Soil Moisture in the Lower Reaches of the Heihe River Under Climate Change

As global climate change intensifies, arid land ecosystems face increasing challenges. Vegetation, a key indicator of climate variation, is highly responsive to meteorological factors such as temperature (Tem), precipitation (Pre), and soil moisture (SM). Understanding how fractional vegetation cover (FVC) responds to climate change in arid regions is critical for mitigating its impacts. This study utilizes MOD13Q1-NDVI data from 2000 to 2022, alongside corresponding Tem, Pre, and SM data, to explore the dynamics and underlying mechanisms of SM and FVC in the context of climate change. The results reveal that both climate change and human activities exacerbate vegetation degradation, underscoring its vulnerability. A strong correlation between FVC and both Tem and Pre suggests that these factors significantly influence FVC variability. In conclusion, FVC in the lower reaches of the Heihe River is shaped by a complex interplay of Tem, Pre, SM, and human activities. The findings provide a scientific basis and decision-making support for ecological conservation and water resource management in the lower reaches of the Heihe River, aiding in the development of more effective strategies to address future climate challenges.

Synthesis and Evaluation of Novel Ternary MgFe2O4/CuO/TiO2 Nanocomposite for Visible Light Photodegradation of Malachite Green Dye

Novel ternary MgFe2O4/CuO/TiO2 nanocomposite was synthesized using the sol-gel method at low temperatures. The XRD, FTIR, SEM-EDX, TEM, UV-visible DRS and VSM techniques were used to characterize the structure, shape, optical, morphology and magnetic properties. The XRD examination revealed typical peaks in nanocomposites, including the anatase phase of TiO2 with an average diameter of 9 nm, consistent with the TEM data. The SEM morphology examinations revealed spherical particles, while EDAX analysis indicated the corresponding components (Fe, Ti, O, Mg and Cu) in the prepared nanocomposites. The UV-DRS measurements revealed that the synthesized nanocomposite has a band-gap energy of 2.30 eV. The vibrating sample magnetometer (VSM) was used to trace the M-H loop of MgFe2O4, yielding magnetic parameters such as saturation magnetization (Ms). The catalytic activity of the as-prepared sample was examined by the degradation of malachite green dye under visible light and UV irradiations. The photocatalytic studies demonstrated that MgFe2O4/CuO/TiO2 nanocomposite showed 100% degradation efficiency towards malachite green dye. Under visible light and UV irradiations, the synthesized MgFe2O4/CuO/TiO2 sample with a molar ratio of 0.8:0.1:0.1 demonstrated good catalytic efficiency. The antibacterial activity investigations were done against Gram-negative Escherichia coli, Klebsiella pneumonia, Gram-positive Staphylococcus aureus and Bacillus subtilis bacteria utilizing nanocomposites.

Boosting ciprofloxacin and indigo carmine dye photodegradation using S-scheme plate-like BiOI@sulfated TiO2 heterojunctions: An understanding of the performance, the degradation route, and DFT computation

Sustainable BiOI/sulfated TiO2 nanocomposites were created for the present study utilizing the environmentally friendly dispersion-ultrasonication technique. Then, their ability to degrade the medication ciprofloxacin (CIP) and indigo carmine coloring (IC) in aquatic water was evaluated. The optimized catalyst 10%BiOI/ST, denoted as 10BOST together with 5BOST, is subjected to thorough characterization together with that of sulfate-free TiO2 (10BOT) to assess their physiochemical, morphological, textural, structural, and elemental composition properties. It is noteworthy that the 10BOST composite achieves remarkable degradation and performs exceptionally well in photocatalytic IC and CIP degradation. In 35 min, it degrades IC to 100%, with a rate constant of 0.066 min−1, which is superior to that of 10BOT (0.054 min−1) in the incidence of visible light and without an oxidizing agent. In CIP, 10BOST yields 85.6% degradation with a rate constant of 0.027 min−1 preceding 0.024 min−1 for 10BOT when potassium persulfate oxidizing agent is present. This exceptional performance is ascribed to the composite's diminished particle diameter, largest pore radius, hydrophilicity, improved light absorption, and the developed heterojunction between ST and BiOI, as demonstrated by XPS, TEM, XRD, EDX and IR data. The effect of sulfation concentration, pH, Ti3+/Ti4+ ratio, and pollutant concentration were studied together with the active species determinations, which revealed that active radicals like SO4•−, •OH, and h+ were well participated in the pollutant's decomposition. Testing for toxicity shows that during CIP breakdown, innocuous hazardous intermediates evolve with a notable 70% mineralization rate in their TOC. Furthermore, 10BOST showed strong stability and reusability. Using DFT simulations, profound insights into the principles underlying the adsorption sites of pollutants, their chemical reactivity, and the arrangement of their electrical charges, and how these factors affect the reaction mechanism on BOST photocatalysts.

Synthesis, characterization, and novel reactivity of nano CeO2 catalyst for solvent-free Knoevenagel condensation

We synthesized the nano CeO2 using the sol-gel method and characterized the material using different techniques, including XRD, FT-IR, BET surface area, SEM, and TEM analysis. We tested the catalytic functionalities of nano CeO2 catalyst for Knoevengel condensation of different substituted benzaldehydes with malononitrile, which offered exceptional 95 % conversion and yield. The results support that nano CeO2 material significantly boosted the yield of the desired product compared to the bulk material. The low-angle XRD profile showed that the regenerated nanomaterial fully retained the porous nature and cubic structure of ceria. FT-IR results reveal that the characteristic vibrational IR band is at 720 cm−1, which is attributed to Ce–O–Ce stretching. The BET surface area result indicates that nano-ceria possesses a higher surface area than bulk CeO2 material. The SEM analysis illustrates cube-like morphology and TEM data show the nanorod-like appearance of ceria. The nanocatalyst exhibited stable and sustainable activity during regeneration up to 5 cycles.

Effect of Synthesis Conditions on the Composition, Local Structure and Electrochemical Behavior of (Cr,Fe,Mn,Co,Ni)3O4 Anode Material

AbstractDisordered high entropy spinels (HES) (Cr,Fe,Mn,Co,Ni)3O4 were obtained by solid‐state synthesis and co‐precipitation using various powder precursors. They were characterized by a complex of physico‐chemical methods and investigated as anode materials for lithium‐ion batteries (LIBs). According to XRD and TEM data, the materials are single‐phase. The structural characterization of the samples obtained at 773, 973, and 1273 K was determined using Raman and Mössbauer spectroscopy, and magnetic measurements. The degree of spinel inversion and lattice distortion (microstrains) decrease with increasing synthesis temperature, while the crystallite size increases. The insufficient nickel content in the samples ensures a more uniform distribution of iron cations in both sublattices, which leads to an increase in the lattice parameters and has a positive effect on the de‐/lithiation. Repeated ball‐milling of HES material, prepared by co‐precipitation, increases its specific capacity from 284 mAh g−1 to 492 mAh g−1 at a current density of 100 mA g−1 after 25 cycles. Besides, the smaller crystallite size reduces the volume changes in the materials during de‐/lithiation.

Small Organic Molecule‐Assisted Mesoscopic Self‐Assembly of SnO2 Nanoparticles: An Efficient Catalyst for the Synthesis of β‐Nitroaldol

AbstractOver the past few decades, huge number of mesoporous materials have been synthesized by using supramolecular assembly of ionic/non‐ionic surfactants as structure‐directing agents (SDAs). Here, we report a facile synthetic strategy to fabricate self‐assembled SnO2 nanoparticles with well‐defined nanocrystalline spherical morphology and mesoporosity using sodium salicylate as a SDA and stabilizing agent. The mesophases of the materials were investigated by powder X‐ray diffraction, TEM and N2 sorption studies. TEM results show that the mesopores are formed by the assembly of ultrasmall SnO2 NPs with broad range of interparticle voids and N2 sorption studies agreed well with this TEM data. This synthesis strategy facilitated the generation of SnO2 NPs with increased surface area and pores of nanoscale dimensions with a large number of exposed surface‐active sites. The photoinduced electron transfer in these materials was investigated by the fluorescence quenching study with pyranine, which suggested the presence of surface Lewis basicity. The materials showed excellent catalytic activity for the synthesis of β‐nitroaldol through the reaction of benzaldehyde and nitromethane. The heterogeneous nature of the catalyst could be attributed to the high surface area, presence of numerous surface active sites, and structural robustness of the self‐assembled SnO2 nanostructure. The catalysts exhibited negligible loss in activity after several catalytic cycles.

Influence of gold-selenium precursor ratio on synthesis and structural stability of α- and β- AuSe

Gold selenide (AuSe) is a multilayer compound that has yet to be thoroughly studied. The colloidal synthesis and characterization of gold selenide nanoparticles are described, emphasizing the effect of different gold-to-selenium precursor ratios and temperatures on the crystal structure and form. The structural characterization is done using an X-ray diffraction pattern. The coexistence of the α- and β-AuSe phases is observed in all synthesized samples. Our research indicates that the β-AuSe phase was predominantly found in the AuSe preparation process, which involved the reaction of metallic gold with elemental Se in oleylamine at a 1:1 precursor ratio of Au/Se. On the other hand, the mixed phase, which was dominated by the α-phase, was found in the selenium-rich synthesis, which had a 1:4 precursor ratio of Au/Se. The morphologies of the mainly α-AuSe sample are nanobelts, whereas the primarily β-AuSe phase sample has a nanoplate-like structure, according to the TEM and SEM data. All of the samples had Raman vibrational modes with mixed phases. The effect of high pressure on as-prepared AuSe samples has been studied in this work. The introduction of external pressure and temperature allows both phases to transition. The rising pressure reduces the presence of β-phase in the mixed phase sample, which has a pre-dominating α-phase, leaving only a substantial α-phase in the AuSe sample. The phase transition pressure was observed using Raman scattering. Our findings show that 2D AuSe has a lot of promise for multifunctional applications, encouraging more research on these systems.

Biosynthesis of Silver and Gold Nanoparticles Using Geum urbanum L. Rhizome Extracts and Their Biological Efficiency

AbstractThe present study evaluates the biosynthesis of AgNPs and AuNPs using aqueous and ethanolic Geum urbanum L. rhizome extracts. The biosynthesized metal nanoparticles (MNPs) were characterized using UV-Vis spectroscopy, FTIR, DLS, SEM, EDX, and TEM. The UV-Vis spectra confirmed the synthesis of AgNPs and AuNPs through peaks corresponding to the surface plasmon effect of metallic Ag (400–430 nm) and Au (530–570 nm). FTIR analysis indicated that alcohols, phenols, proteins, and carbohydrates from G. urbanum rhizome extracts composition are involved in MNPs synthesis. In DLS analysis, AgNPs (34.26–41.14 nm) showed smaller hydrodynamic diameters than AuNPs (46.26–70.29 nm). At the same time, all values for zeta potential were negative, between − 21 and − 13 mV, suggesting good stabilities for all the colloidal MNPs systems in dispersion. TEM analysis showed that the biosynthesized AgNPs had a spherical morphology, while AuNPs were quasi-spherical, polygonal, and triangular. According to TEM data, AgNPs synthesized using aqueous and ethanolic G. urbanum rhizome extracts were characterized by mean diameters of 9.82 ± 3.68 and 14.29 ± 3.46 nm, while AuNPs by 15.88 ± 6.28 and 24.89 ± 10.75 nm, respectively. EDX analysis confirmed the presence of metallic Ag and Au in the MNPs composition by detecting strong signals at 3 (AgNPs) and 2.2 keW (AuNPs). In disc diffusion assay, MNPs showed good antimicrobial activity against Gram-positive (S. aureus MSSA, S. aureus MRSA, S. epidermidis) and Gram-negative (E. coli, P. aeruginosa, K. pneumoniae) bacteria and yeasts (C. albicans). AgNPs and AuNPs were also characterized by a significant antioxidant potential, evaluated through in vitro assays (lipoxygenase inhibition, DPPH radical scavenging activity, metal ion chelating activity, and hydroxyl radical scavenging assays). An overall better activity was obtained for the ethanolic G. urbanum rhizome extract and its derived AgNPs (EC50 = 34.2 ± 1.86 mg/mL in lipoxygenase inhibition assay). Therefore, the G. urbanum rhizome extracts proved to be excellent sources for biologically active AgNPs and AuNPs.

A novel pH-sensitive drug carrier system based on 18-crown ether-6/sodium alginate for curcumin/nido-carborane encapsulation: Studies of release properties, cell imaging and bioactivity evaluation

Curcumin's remarkable anti-tumor action has drawn a lot of interest, however its low bioavailability, poor targeting, and poor water solubility restrict its therapeutic potential. Two fluorescent polymers based on curcumin/nido-carborane-crown ether were produced using a two-phase technique in this study: Cur/Carborane-C/SA (encapsulated with sodium alginate) and Cur/Carborane-C (without sodium alginate). Cur/Carborane-C/SA was thought to be the most promising polymer with anti-tumor properties. The drug delivery method based on the polymer created by tris (3-aminoethyl) amine (TAEA) and 18-crown ether-6 in combination with sodium alginate offers a novel approach to curcumin encapsulation technology. Nido-carborane improves the targeting of curcumin and its tumor-cell-inhibiting properties. Good fluorescence qualities were shown by Cur/Carborane-C/SA's fluorescence quantum yield of 0.119 %. According to in vitro drug release data, the polymer performed well for pH response release at 5.0. The TEM and particle size data demonstrated that curcumin produced uniformLy sized, difficult to agglomerate nanoparticles with a particle size of less than 300 nm. The polymer exhibited a substantial affinity and inhibition of HCT-116 and HeLa cells, with an inhibition rate that may reach 78.3 %, according to the findings of the cytotoxicity assay and cell imaging. As a result, it is anticipated that the produced Cur/Carborane-C/SA would provide a new pH-responsive drug carrier system for curcumin intended for use in cancer treatment.

Efficient sonocatalytic degradation of pyrene using a novel and magnetically recoverable graphitic carbon nitride – cobalt ferrite – graphene oxide (g-C3N4/CoFe2O4@GO) nanocomposite with an enhanced Z-scheme electron transfer pathway

The use of ultrasound in the presence of semiconductor materials is considered a novel technique for the degradation of hazardous organic pollutants in water. In this study, graphitic carbon nitride (g), graphene oxide (GO), and Cobalt ferrite, CoFe2O4 (CF) nanoparticles were synthesized via soft-template-assisted synthesis, Hummer's, and hydrothermal methods, respectively. Subsequently, the hybrid magnetic g-C3N4/CoFe2O4/GO (g-CF1@GO, g-CF2@GO, g-CF3@GO, and g-CF4@GO) nanocomposites were prepared via a simple hydrothermal route at 180 °C. The crystallite structure, functional groups, morphology, and energy band gaps were characterized by XRD diffraction, FT-IR, TEM, and UV–vis DRS. The heterostructure nanocomposites were formed, as evidenced by the TEM data, with an average crystallite size of 13.4 nm and band gap energies of 2.19–1.80 eV, suggesting their suitability for sono/photo degradation processes. Pyrene, a tetracyclic polycyclic aromatic hydrocarbon (PAH) was chosen as a model pollutant to evaluate the performance of the prepared nanocomposites toward sonocatalytic degradation. The nanocomposites exhibited higher degradation performances than individual materials. The sonocatalytic degradation of pyrene revealed that the g-CF4@GO nanocomposite exhibited the highest sonocatalytic activity and achieved 86.7 and 92.3 % degradation efficiency for 10 and 5 mg/L of pyrene under ultrasonic irradiation (40 mg/L, 50 W and 20 kHz) in 120 min. In addition, the sonocatalytic degradation of pyrene is performed in the absence of any oxidant and follows a pseudo-first-order kinetics. Trapping experiments were carried out to investigate the sonocatalytic degradation mechanism, and the results showed that ●O2− was the major reactive species. The easily recoverable magnetic nanocomposite via a simple magnet was tested for its recyclability and reusability, and it was observed that it could degrade up to 78 % of pyrene in four cycles.

Effect of Pd content in multi-component alloys [CoFeNi]Pdx on their behavior in hydrocarbon-containing atmosphere

Multicomponent metal systems attract growing interest today, especially as catalysts for various processes. In the present work, a series of [CoFeNi]Pdx alloys (equal atomic content of base metals) doped with palladium in the amount of 0–10 at.% were synthesized via thermolysis of multicomponent precursors. The resulting [CoFeNi]Pdx alloys were found to be single-phase solid solutions with a fcc structure represented by agglomerates of grains fused. The performance of the alloys was explored in a mixture of saturated hydrocarbons (C2–C4) within the temperature range of 600–675 °C. As a result of interaction with the reaction mixture, spontaneous disintegration of the alloys containing above 2 at.% Pd occurs with the formation of dispersed particles responsible for the catalytic growth of carbon nanofibers (CNF). The dependence of the productivity of the [CoFeNi]Pdx alloys towards CNFs on the x parameter was studied. The highest CNF yield (YC = 25–46 g/gcat, 30 min) was achieved at an optimal Pd concentration of 8 at.% within the entire temperature range. According to TEM and EDX data, regardless of the reaction temperature and Pd concentration in the alloy, the catalyst particles have the same composition as defined at the synthesis of the alloys. The resulting CoFeNiPd@CNF composite can be considered as a catalyst for other heterogeneous catalysis processes.

Borides Mn3-x{Rh,Ir}5B2 with Ti3Co5B2-type: X-ray single crystal and TEM data, physical properties

A cursory investigation of the phase relations in the Mn-{Rh,Ir}-B systems prompted for each system a ternary compound, Mn3-x{Rh,Ir}5B2, the crystal structure of them was determined from X-ray single crystal data to be isotypic with the Ti3Co5B2-type (space group P4/mbm, No. 127). In both cases the Mn-site in 2a at the origin of the unit cell exhibits a significant defect (or Mn/B substitution). Transmission electron microscopy studies confirm the absence of a superstructure related to these defects/disorder. The two phases, Mn3-xRh5B2 (x∼0.34) and Mn3-xIr5B2 (x∼0.85) at 950 °C show rather limited homogeneity regions pointing towards higher Mn-contents. Whereas temperature dependent magnetization and specific heat measurements of Mn2.15Ir5B2 do not reveal any indication for a magnetic phase transition in the temperature range from 3 to 300 K, a broad specific heat anomaly at around 200 K and a tilde shape of the temperature dependent magnetization of Mn2.66Rh5B2 appears indicative of an antiferromagnetic phase transition. The latter is also reflected by an anomaly of the electrical resistivity (ρ; 4–300 K) of Mn2.66Rh5B2 which displays a non-monotonous temperature dependence, whereas ρ(T) of Mn2.15Ir5B2 displays a simple metallic-like behavior dominated by scattering from defects. Elastic moduli and Poisson's ratio were determined at room temperature from Resonant Ultrasonic Spectroscopy (RUS) data yielding Young's moduli of E ∼ 170 GPa for Mn2.66Rh5B2 and E ∼ 210 GPa for Mn2.15Ir5B2. Vickers hardness HV is lower for Mn2.66Rh5B2 (HV = 590 ≅ 5.79 GPa) than for Mn2.15Ir5B2 (HV = 655 ≅ 6.42 GPa). The indentation fracture toughness for Mn2.15Ir5B2 was IKC = 0.71 ± 0.5 MPa m1/2.

Synthesis, spectroscopic, biological and structural characterizations for the gold(III), platinum(IV), and Ruthenium(III) ceftriaxone drug complexes

Three new metal complexes of ceftriaxone (cef), incorporating platinum(IV), gold(III), and ruthenium(III), were prepared. The complexes were prepared using a 1:2 molar ratio between ceftriaxone sodium salt (Na2cef) to AuCl3, PtCl4, and RuCl3 salts in methanol solvent. The as-synthesized complexes were characterized using microanalytical techniques for C, H, N, and S elements, magnetic and molar conductance measurements, as well as spectroscopic methods including FTIR, 1H NMR, and UV-Vis. The shape, morphology and size calculations have been examined using SEM, TEM, and X-ray diffraction data. The cef complexes were six-coordinate systems possessing a distorted octahedral geometry. Through the oxygen of both triazine and carboxylate moieties with the chemical formulae [Au(cef)2(Cl)(H2O)] (I), [Pt(cef)2(Cl)2] (II), and [Ru(cef)2(Cl)(H2O)] (III) the antibiotic cef acts as a bidentate ligand towards three metal ions. The newly created complexes demonstrated antibacterial activity showing efficacy in comparison to the cef sodium ligands. In vitro, antibacterial assays against specific microorganisms were evaluated to assess the antibacterial activities of the complexes. Cytotoxicity assays for cef complexes were conducted for HepG-2 and MCF-7 cell lines, representing human hepatocellular carcinoma and breast cancer, respectively. A value of 22.4 g and 26.2 g for 50% inhibitory concentration (IC50), respectively, for HepG-2 and MCF-7 were obtained for [Ru(cef)2(Cl)(H2O)] (III). KEY WORDS: Ceftriaxone sodium, Gold, Ruthenium, Platinum, Complexes, FTIR, IC50 Bull. Chem. Soc. Ethiop. 2024, 38(4), 937-948. DOI: https://dx.doi.org/10.4314/bcse.v38i4.10

Structural studies of a serum amyloid A octamer that is primed to scaffold lipid nanodiscs.

Serum amyloid A (SAA) is a highly conserved acute-phase protein that plays roles in activating multiple pro-inflammatory pathways during the acute inflammatory response and is commonly used as a biomarker of inflammation. It has been linked to beneficial roles in tissue repair through improved clearance of lipids and cholesterol from sites of damage. In patients with chronic inflammatory diseases, elevated levels of SAA may contribute to increased severity of the underlying condition. The majority of circulating SAA is bound to lipoproteins, primarily high-density lipoprotein (HDL). Interaction with HDL not only stabilizes SAA but also alters its functional properties, likely through altered accessibility of protein-protein interaction sites on SAA. While high-resolution structures for lipid-free, or apo-, forms of SAA have been reported, their relationship with the HDL-bound form of the protein, and with other possible mechanisms of SAA binding to lipids, has not been established. Here, we have used multiple biophysical techniques, including SAXS, TEM, SEC-MALS, native gel electrophoresis, glutaraldehyde crosslinking, and trypsin digestion to characterize the lipid-free and lipid-bound forms of SAA. The SAXS and TEM data show the presence of soluble octamers of SAA with structural similarity to the ring-like structures reported for lipid-free ApoA-I. These SAA octamers represent a previously uncharacterized structure for lipid-free SAA and are capable of scaffolding lipid nanodiscs with similar morphology to those formed by ApoA-I. The SAA-lipid nanodiscs contain four SAA molecules and have similar exterior dimensions as the lipid-free SAA octamer, suggesting that relatively few conformational rearrangements may be required to allow SAA interactions with lipid-containing particles such as HDL. This study suggests a new model for SAA-lipid interactions and provides new insight into how SAA might stabilize protein-lipid nanodiscs or even replace ApoA-I as a scaffold for HDL particles during inflammation.

Synergistic reduction of nitrophenols by Au-CDs nanoconjugates with NaBH4

Developing sustainable and innovative approaches for the efficient reduction of nitrophenols is crucial for environmental remediation, for managing health concerns posed by their widespread presence as hazardous pollutants in industrial effluents and contaminated water. We report the use of 12.9 ± 1 nm (TEM data) sized gold carbon dot nanoconjugates (Au@CDs) for catalytic conversion of o, m, p-nitrophenols to aminophenols by sodium borohydride. A simple approach was followed to synthesize ultra-small and highly stable Au@CDs, using citric acid and PEG as reducing and stabilizing agents. X-ray diffraction analysis verified the formation of nano-crystalline nanoconjugates. These nanoconjugates showed a remarkable catalytic activity in the range of 0.22–0.33 s−1 (varying with nanoconjugate concentration) which was much higher compared to conventional chemical methods of reduction. All the catalytic reaction experiments were performed at room temperature (27 ± 2 °C). Furthermore, an increase in rate constant was observed with increasing concentration of nanoconjugates. The catalytic activity of Au@CDs nanoconjugates was observed to be in order of m-nitrophenol > o-nitrophenol > p-nitrophenol with apparent rate constant (k aap) values of 0.068, 0.043 and 0.031, respectively. Comparative analysis with GNPs, CDs and Au@CDs nanoconjugates stated that the nanoconjugates had superior catalytic activity. The research can have significant implications in the development of new strategies for environmental remediation and biomedical applications.

The in vitro and in vivo depigmentation activity of coenzyme Q0, a major quinone derivative from Antrodia camphorata, through autophagy induction in human melanocytes and keratinocytes

BackgroundCoenzyme Q0 (CoQ0), a novel quinone derivative of Antrodia camphorata, has been utilized as a therapeutic agent (including antioxidant, anti-inflammatory, antiangiogenic, antiatherosclerotic, and anticancer agents); however, its depigmenting efficiency has yet to be studied.MethodsWe resolved the depigmenting efficiency of CoQ0 through autophagy induction in melanoma (B16F10) and melanin-feeding keratinocyte (HaCaT) cells and in vivo Zebrafish model. Then, MPLC/HPLC analysis, MTT assay, Western blotting, immunofluorescence staining, LC3 transfection, melanin formation, GFP-LC3 puncta, AVO formation, tyrosinase activity, and TEM were used.ResultsCoQ0-induced autophagy in B16F10 cells was shown by enhanced LC3-II accumulation, ATG7 expression, autophagosome GFP-LC3 puncta, and AVOs formation, and ATG4B downregulation, and Beclin-1/Bcl-2 dysregulation. In α‐MSH-stimulated B16F10 cells, CoQ0 induced antimelanogenesis by suppressing CREB-MITF pathway, tyrosinase expression/activity, and melanin formation via autophagy. TEM data disclosed that CoQ0 increased melanosome-engulfing autophagosomes and autolysosomes in α‐MSH-stimulated B16F10 cells. CoQ0-inhibited melanogenesis in α‐MSH-stimulated B16F10 cells was reversed by pretreatment with the autophagy inhibitor 3-MA or silencing of LC3. Additionally, CoQ0-induced autophagy in HaCaT cells was revealed by enhanced LC3-II accumulation, autophagosome GFP-LC3 puncta and AVO formation, ATG4B downregulation, ATG5/ATG7 expression, and Beclin-1/Bcl-2 dysregulation. In melanin-feeding HaCaT cells, CoQ0 induced melanin degradation by suppressing melanosome gp100 and melanin formation via autophagy. TEM confirmed that CoQ0 increased melanosome-engulfing autophagosomes and autolysosomes in melanin-feeding HaCaT cells. Treatment with 3-MA reversed CoQ0-mediated melanin degradation in melanin-feeding HaCaT cells. In vivo study showed that CoQ0 suppressed endogenous body pigmentation by antimelanogenesis and melanin degradation through autophagy induction in a zebrafish model.ConclusionsOur results showed that CoQ0 exerted antimelanogenesis and melanin degradation by inducing autophagy. CoQ0 could be used in skin-whitening formulations as a topical cosmetic application.

Hydrogenation of Cinnamaldehyde Using Carbon Dots Reduced Palladium Nanoparticles

Carbon dots (CDs) with a size range of 0.2 to 2 nm were prepared using a hydrothermal treatment of sucrose and oleic acid. The as-synthesized CDs were used to reduce H2PdCl4 to metallic Pd nanoparticles with dPd = 9.3 ± 3.7 nm, as confirmed by PXRD and HRTEM data. Pd particles were made to be larger than the CDs, to observe any inverse support effects, however, TEM data revealed that the CDs were transformed to carbon sheets in the reduction reaction at 100 °C. The synthesized Pd-CDs catalysts (0.81 wt. % loading) and CDs were both tested for the liquid phase hydrogenation of cinnamaldehyde. The influence of mass, temperature, and hydrogen flow rate on the activity and selectivity of the CDs and Pd-CDs catalyst on the hydrogenation of cinnamaldehyde was investigated. The CDs gave a cinnamaldehyde conversion (40%, 4 h) with selectivity towards the reduction of the C = O bond (cinnamyl alcohol) while the Pd-carbon catalyst was only selective to the reduction of the C = C bond (conversion 78%) indicating the dominance of Pd in the reaction. Post analysis of the deactivated catalysts indicated formation of carbon sheets and sintering of the Pd nanoparticles. It is thus shown that the presence of Pd induces the CDs to carbon sheet formation and thus indicates the limited use of CDs as a support for the olefin hydrogenation reaction with the CDs produced carbon support. This finding has implications for other studies using CDs as supports.Graphical abstract

Photocatalytic Removal of Metronidazole Antibiotics from Water Using Novel Ag-N-SnO2 Nanohybrid Material.

In this study, we employed a straightforward synthetic approach using the sol-gel method to fabricate a novel photocatalyst, Ag and N co-doped SnO2 (Ag-N-SnO2). The synthesized photocatalysts underwent characterization through various techniques including XRD, FTIR, FESEM-EDS, TEM, UV-vis DRS, BET, and XPS. The UV-vis DRS results confirmed a reduction in the bandgap energy of Ag-N-SnO2, leading to enhanced absorption of visible light. Additionally, TEM data demonstrated a smaller particle size for Ag-N-SnO2, and BET analysis revealed a significant increase in surface area compared to SnO2.The efficiency of the Ag-N-SnO2 photocatalyst in degrading metronidazole (MNZ) under natural sunlight surpassed that of SnO2. Under optimal conditions (Ag-N-SnO2 concentration of 0.4 g/L, MNZ concentration of 10 mg/L, pH 9, and 120 min of operation), the highest MNZ photocatalytic removal reached 97.03%. The reaction kinetics followed pseudo-first-order kinetics with a rate constant of 0.026 min-1. Investigation into the mineralization of MNZ indicated a substantial decrease in total organic carbon (TOC) values, reaching around 56% in 3 h of sunlight exposure. To elucidate the photocatalytic degradation mechanism of MNZ with Ag-N-SnO2, a scavenger test was employed which revealed the dominant role of •O2-. The results demonstrated the reusability of Ag-N-SnO2 for up to four cycles, highlighting its cost-effectiveness and environmental friendliness as a photocatalyst.

Refinement technique for nanocellulose extraction from corn cobs as a green material for environmental sustainability

Corn cob and other types of agricultural biomass waste are abundant and have several potential uses as renewable materials. A unique extraction approach for producing nanocellulose materials with precise control, scalability, and promising practical applications has been presented. Nanocrystalline cellulose was produced from corn cobs by mechanical treatment with ultrasonic technology, room temperature extraction for 30 min, and sulfuric acid concentrations ranging from 30% to 60% w/v. Nanocellulose has been effectively extracted from maize cobs with comparatively high yields and crystallinities ranging from 63.55% to 71.76%. The TEM data demonstrate the production of fiber nanoparticles with a size range of 15.3 nm to 2.1 nm. Simultaneously, SEM results match TEM findings. SEM pictures indicate smaller nanoparticles as sonication duration rises, but particle size does not vary with acid content. XRD analysis indicates an increase in the amount of crystalline cellulose in nanocellulose, demonstrating a notable transformation of cellulose. Nanocellulose and cellulose had similar FTIR spectra, distinct from the basic material of corn cobs. The FTIR analysis showed that the NaOH and subsequent bleaching treatments eliminated most hemicellulose and nearly all lignin throughout the conversion process. This work introduces a method for extracting nanocellulose from corncob waste utilizing standard ultrasonic technology under moderate conditions, at a cheap cost, in an ecologically responsible manner, with a high yield while maintaining its integrity.

TEMsuite – A Matlab-based software platform for TEM data analysis

TEMsuite – A Matlab-based software platform for TEM data analysis