Transmission Electron Microscopy Methods Research Articles

Granular activated carbon supported polyethylene glycol modified nano-zero-valent iron immobilized microbial removal of 2,4-dichlorophenol in water

In recent years, the remediation of 2,4-DCP pollution using immobilized microbial technology has attracted increasing attention. Using granular activated carbon (GAC), polyethylene glycol 4000 (PEG-4000), ferrous sulfate, and sodium borohydride as raw materials, granular activated carbon loaded polyethylene glycol modified nano zero-valent iron composite material (PEG-nZVI/GAC) was prepared via a liquid-phase reduction method. Bacillus marisflavi, capable of degrading phenolic compounds, was immobilized on PEG-nZVI/GAC using an adsorption method to prepare immobilization of microorganisms by granular activated carbon loaded polyethylene glycol modified nano zero-valent iron (PEG-nZVI/GAC@B) for 2,4-DCP removal. Characterization analysis of immobilized microbes was conducted using transmission electron microscopy (TEM) and other methods to determine their physicochemical properties. Response surface methodology (RSM) was employed to optimize the conditions for 2,4-DCP removal, and the performance and mechanism of 2,4-DCP removal by PEG-nZVI/GAC@B were studied. The results indicate that nanoscale zero-valent iron (nZVI) was uniformly distributed in granular activated carbon, Bacillus marisflavi was successfully loaded onto PEG-nZVI/GAC, PEG-nZVI/GAC@B had a higher content of oxygen-containing groups on its surface, and exhibits good dispersibility, stability, and reusability. When the immobilized microbial dosage was 270.32 mg/L, the initial concentration of 2,4-DCP was 50.51 mg/L, and pH was 6.58, the predicted removal rate of 2,4-DCP was 96.53 %. Under these conditions, the actual removal rate of 2,4-DCP was 94.68 %. The removal of 2,4-DCP by PEG-nZVI/GAC@B involved adsorption by granular activated carbon, reductive dechlorination by nanoscale zero-valent iron, and degradation by Bacillus marisflavi. In conclusion, PEG-nZVI/GAC@B is an excellent immobilized microorganism for the removal of 2,4-DCP.

Synthesis, Characterization, and Cytotoxicity Evaluations of Silver–Zeolite Nanocomposite

Zeolites of natural origin are materials exhibiting many positive effects on the human body. Silver-modified zeolites have already been introduced as bactericidal agents, although studies dealing with their toxicity are insufficient. This work describes the synthesis of activated and silver-loaded Bulgarian zeolite using a simple wet impregnation method. Morphological characteristics and compositions of natural zeolite, activated zeolite, and Ag-nanocomposites were studied by the X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. Silver loading is approximately 13 wt. %, with mean Ag particle size around 19 nm. Analyses of the samples included antioxidant activity assays based on ABTS radical scavenging ability and in vitro cytotoxicity tests with human normal fibroblasts and three adenocarcinoma cell lines. The experiments were performed with natural, activated, and Ag-modified zeolite in comparison to two commercial food supplements. Our results indicated moderate antioxidant activity of the tested samples. Silver-modified zeolite demonstrated cytotoxic effects against both tumor cells and normal fibroblasts, but the detected levels of inhibition were stronger against the adenocarcinoma cells, suggesting anti-tumor potential. The present article indicates a new aspect of Bulgarian natural zeolite and Ag-loaded zeolite biological activity. It highlights the need for detailed toxicity evaluations of Ag-nanocomposites prior to healthcare applications.

MCF-7 cell - derived exosomes were involved in protecting source cells from the damage caused by tributyltin chloride via transport function

Tributyltin chloride (TBTC) is a ubiquitous environmental pollutant with various adverse effects on human health. Exosomes are cell - derived signaling and substance transport vesicles. This investigation aimed to explore whether exosomes could impact the toxic effects caused by TBTC via their transport function. Cytotoxicity, DNA and chromosome damage caused by TBTC on MCF-7 cells were analyzed with CCK-8, flow cytometry, comet assay and micronucleus tests, respectively. Exosomal characterization and quantitative analysis were performed with ultracentrifugation, transmission electron microscope (TEM) and bicinchoninic acid (BCA) methods. TBTC content in exosomes was detected with Liquid Chromatography-Mass Spectrometry (LC-MS). The impacts of exosomal secretion on the toxic effects of TBTC were analyzed. Our data indicated that TBTC caused significant cytotoxicity, DNA and chromosome damage effects on MCF-7 cells, and a significantly increased exosomal secretion. Importantly, TBTC could be transported out of MCF-7 cells by exosomes. Further, when exosomal secretion was blocked with GW4869, the toxic effects of TBTC were significantly exacerbated. We concluded that TBTC promoted exosomal secretion, which in turn transported TBTC out of the source cells to alleviate its toxic effects. This investigation provided a novel insight into the role and mechanism of exosomal release under TBTC stress.

Bioaccumulation of Pb in the Gills of Perna viridis (Bivalvia: Mytilidae) in Jakarta Bay, Indonesia and its Histological Alteration

Pollution in Jakarta Bay associated with terrestrial run-off and eutrophication. Bivalves have been recognized as aquatic organisms that play the most dominant role in aquatic ecosystems. Pb is an element that in many cases causes health problems in the liver, kidneys, hematopoietic system and nervous system. This study aims to analyze the bioaccumulation of Pb in the gills of P. viridis in Jakarta Bay, and its histological changes. Bioaccumulation analysis using the AAS and histology changes using transmission electron microscopy (TEM) methods. The results of AAS, showed that the value of Pb concentration in gill tissue at the two seasons did not show a noticeable difference. Pb concentrations in gills were lower at 1, 4, and 5 than at 2 and 3 stations. The results of ultrastructure analysis as an impact of Pb accumulation showed that thickening of the nucleus membrane, and a decrease in the number of microvilli. The thickening of the nucleus membrane, and the decrease in the number of microvilli are cellular responses to the entry of the Pb heavy metal into the cell. Besides, the results of this study showed inflammation, a decrease in the number of mitochondria, as well as causing cristae to be empty.

Study of the anti-cancer activity of a mesoporous silica nanoparticle surface coated with polydopamine loaded with umbelliprenin

A mesoporous silica nanoparticle (MSN) coated with polydopamine (PDA) and loaded with umbelliprenin (UMB) was prepared and evaluated for its anti-cancer properties in this study. Then UMB-MSN-PDA was characterized by dynamic light scattering (DLS), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM) and FTIR methods. UV-visible spectrometry was employed to study the percentage of encapsulation efficiency (EE%). UMB-MSN-PDA mediated cell cytotoxicity and their ability to induce programmed cell death were evaluated by MTT, real-time qPCR, flow cytometry, and AO/PI double staining methods. The size of UMB-MSN-PDA was 196.7 with a size distribution of 0.21 and a surface charge of −41.07 mV. The EE% was 91.92%. FESEM and TEM showed the spherical morphology of the UMB-MSN-PDA. FTIR also indicated the successful interaction of the UMB and MSN and PDA coating. The release study showed an initial 20% release during the first 24 h of the study and less than 40% during 168 h. The lower cytotoxicity of the UMB-MSN-PDA against HFF normal cells compared to MCF-7 carcinoma cells suggested the safety of formulation on normal cells and tissues. The induction of apoptosis in MCF-7 cells was indicated by the upregulation of P53, caspase 8, and caspase 9 genes, enhanced Sub-G1 phase cells, and the AO/PI fluorescent staining. As a result of these studies, it may be feasible to conduct preclinical studies shortly to evaluate the formulation for its potential use in cancer treatment.

Preparation and Capacitive Properties of Ni-Doped Zinc Cobaltate/Carbon Fiber Composite Porous Mesh Materials

Nickel-element-doped zinc cobaltate/carbon fiber composites (Ni-ZnCo2O4/CF) were prepared on carbon cloth (made of a combination of carbon fibers) conductive substrates using a simple ambient stirring method combined with heat treatment. Characterization tests of the materials revealed that the prepared products were porous Ni-ZnCo2O4/CF mesh structures. This porous network structure increases the surface area of the material and helps shorten the diffusion path of ions and electrons. The samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods to investigate the effect of Ni elemental doping on the stability of the materials. The results show that there are no other impurity peaks and no other impurity elements in the Ni-ZnCo2O4/CF electrode material, which indicates that the sample purity is high. Meanwhile, the electrochemical properties of Ni-ZnCo2O4/CF electrode materials were studied. Under the condition of 15 A·g−1, the specific capacitance of Ni-ZnCo2O4/CF electrode material is 1470 F·g−1, and after 100 cycles, its specific capacity reaches 1456 F·g−1, which is 99.0% of the specific capacity of 1470 F·g−1, indicating that the electrode material has good stability. In addition, we assembled asymmetric supercapacitors (Ni-ZnCo2O4/CF//CNTs) with Ni-ZnCo2O4/CF as the positive material and carbon nanotubes (CNTs) as the negative material. In the cyclic stability experiment of Ni-ZnCo2O4/CF/CNTs devices, when the current density was 1 A·g−1, the specific capacitance was 182 F·g−1. After 10,000 cyclic charge–discharge tests, the specific capacity became 167 F·g−1, which was basically unchanged compared with the initial specific capacity, reaching 91.8%. It shows that it has higher charge–discharge performance and higher cycle stability.

Novel Transmission Electron Microscopic Method to Quantify Protein Clustering on the Cell Surface.

The cell surface distribution patterns (clustering) of membrane proteins have been widely investigated in cell biology. Here we describe a novel transmission electron microscopic (TEM) protocol designed to improve the quality of information obtained about the protein distribution patterns detected. This novel method makes it possible to study the clustering of all transmembrane proteins on one half of the cytoplasmic membrane of a whole cell. To achieve better imaging, we combine various methods, including critical-point drying, fixation of gold beads with a carbon layer, and a newly developed chemical thinning method. In addition, in our image-processing algorithm, we implemented pair correlation and pair cross-correlation functions, providing more details and better quantitative accuracy in characterizing the size and numbers of possible protein clusters. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Sample preparation and transmission electron micrography Alternate Protocol: Direct cell labeling for transmission electron micrography Basic Protocol 2: Analysis of TEM images to detect immunogold-labeled proteins.

Антимікробна та противірусна активність нанокомпозитів на основі поліелектролітних комплексів з наночастинками срібла

Recently, nanocomposite materials containing nanoparticles of metals such as silver, copper and zinc oxide have attracted most attention due to their pronounced pharmacological properties, such as antimicrobial, antiviral, antiinflammatory, immunomodulatory ability and high stability in extreme conditions. Polyelectrolyte complexes based on polymers of natural origin, namely polysaccharides of chitosan and pectin, which can stabilize nanoparticles of a smaller size than individual polymers have significant potential for creation of silver-containing nanocomposites. The aim of this article is to study the antimicrobial and antiviral activity of silver-containing nanocomposites based on polyelectrolyte complexes. Methods. Peculiarities of the structural organization of silver-containing nanocomposites were investigated by the method of wide-angle scattering on an XRD-7000 diffractometer. The morphology of Ag nanoparticles in polymer matrixes were studied by transmission electron microscopy method (transmission electron microscope JEOL 100 CXII). The antimicrobial activity of silver-containing nanocomposites was determined by agar diffusion assays against opportunistic pathogens Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. Cytotoxicity and antiviral activity were investigated using the MTT method and staining by gentian violet. Results. Analysis of wide-angle X-ray diffractograms of silver-containing nanocomposites based on polyelectrolyte complexes Na-CMC (pectin) – chitosan showed that at reduction of Ag+ ions to metallic silver, there are two low-intensity diffraction maxima at 2θm ~ 380 and 440 in the diffractograms. These maxima correspond to the crystallographic planes of the face-centered cubic lattice of silver, are characterized by indices (111) and (200), respectively, and confirm the presence of metallic silver in the polymer system. Analysis of micrographs of silver-containing nanocomposites based on Na-CMC and chitosan showed that larger nanoparticles are formed with increasing the molecular weight of chitosan. The dependence of the size of silver nanoparticles on the wavelength of ultraviolet radiation at reduction of silver ion in polyelectrolyte-metal complexes Na-CMC–Ag+–chitosan of low molecular weight was also revealed. In particular, smaller particles are formed under irradiation by light with a shorter wavelength (λ =254 nm) than at λ=365 nm. Silver-containing nanocomposites Na-СMC-Ag-chitosan and pectin citrus-Ag-chitosan, obtained by reduction of Ag+ ions under ultraviolet irradiation at a wavelength λ = 365 nm and λ = 254 nm, exhibit high antimicrobial activity against the test cultures of microorganisms S. aureus, E. coli, and P. aeruginosa C. albicans. No significant dependence of antimicrobial activity on the molecular weight of the studied samples was noted: the obtained data were within close limits and had close values. In addition, no dependence of antimicrobial activity on the type of investigated test cultures of microorganisms was observed either. Nanocomposites based on Na-CMC-chitosan (λ = 365 nm) inhibited infection titer HSV-1 by (3.72–5.45) lgTCID50/mL, whereas the decrease in titer during incubation with samples based on citrus pectin-chitosan was within (2.39–2.42) lgTCID50/mL. A dose-dependent relationship between molecular weight of chitosan and reduction of infection titer was observed. It was found that silver-containing nanocomposites formed by reduction of silver ions in polyelectrolyte-metal complexes under ultraviolet radiation of different wavelengths had no cytotoxic effect on cells of MDCK and BHK. Conclusions. The investigated silver-containing nanocomposites based on Na-CMC (pectin)-chitosan polyelectrolyte complexes show antimicrobial activity against test cultures of S. aureus, E. coli P. aeruginosa, and C. albicans along with antiviral activity against herpes simplex virus type 1 and influenza virus. It was established that the obtained nanocomposites did not show a cytotoxic effect on MDCK and BHK cells. The obtained data allow us to assert that investigated silver-containing nanocomposites are promising antimicrobial means for the development of new effective strategies against microorganisms and viruses and improvement of the population health.

Rapidly solidified Al-Cu-Co quasicrystalline alloy: microstructure and catalytic properties

This study presents the characterisation and evaluation of the catalytic potential of an alloy with a composition referring to the quasicrystal from the Al-Cu-Co system. The material was synthesised through a melt-spinning process, providing rapid solidification conditions and a favourable material form of thin ribbons. Microstructural and chemical analyses were performed using scanning electron microscopy, X-ray diffraction and transmission electron microscopy methods. The obtained results confirmed the presence of a major phase which was a decagonal quasicrystal in the form of globular grains and additional crystalline phases occurring along the grain boundaries. The catalytic potential of the materials was explored using phenylacetylene hydrogenation. The catalyst, obtained by pulverising the ribbons, demonstrated catalytic activity with over 40% phenylacetylene conversion and selectivity exceeding 60% for styrene production under mild reaction conditions. The recovered catalyst displayed a stable phase composition, as confirmed by X-ray diffraction, and unchanged morphology, indicating the possibility of catalyst reuse for subsequent reaction cycles. The presented results provide insight into the experimental verification of the catalytic properties of the developed environmentally friendly catalysts.

Comparison of differential phase Contrast, Lorentz and non-Lorentz transmission electron microscopy for microstructural and magnetic imaging of alnico magnet

In this work, non-Lorentz, Lorentz transmission electron microscopy (LTEM) and differential phase contrast (DPC) methods were used to observe the phase and magnetic structure of the alnico magnet. All observations were performed on alnico-5 in transverse orientation. The results showed the magnetic contrast of the domain walls in the conventional TEM images despite the effects of the lens magnetic field, which was verified and explained using DPC. Experimental methodology and sample results are summarized with advice for further research.

Failure analysis of heavy ion-irradiated silicon carbide junction barrier Schottky diodes

An analysis of damage, including single event burnout (SEB) and single event leakage current (SELC) caused by heavy ion irradiation in silicon carbide (SiC) junction barrier Schottky diodes (JBSDs), was performed using Auger electron spectroscopy (AES), emission microscope (EMMI), focused ion beam (FIB), transmission electron microscopy (TEM) and other methods. The damage of SEB extending from the Schottky contact through the epitaxial layer to the SiC substrate was observed. The damage causing SELC was related to the micro-burnout of the Schottky contact. It was concluded that the damage of Schottky contact was induced by incident high-energy particles under a large electric field, forming a leakage current path, resulting in SEB and SELC in the SiC device.

Delineating the Ultra-Low Misorientation between the Dislocation Cellular Structures in Additively Manufactured 316L Stainless Steel.

Sub-micro dislocation cellular structures formed during rapid solidification break the strength-ductility trade-off in laser powder bed fusion (LPBF)-processed 316L stainless steel through high-density dislocations and segregated elements or precipitates at the cellular boundaries. The high-density dislocation entangled at the cellular boundary accommodates solidification strains among the cellular structures and cooling stresses through elastoplastic deformation. Columnar grains with cellular structures typically form along the direction of thermal flux. However, the ultra-low misorientations between the adjacent cellular structures and their interactions with the cellular boundary formation remain unclear. In this study, we revealed the ultra-low misorientations between the cellular structures in LPBF-processed 316L stainless steel using conventional electron backscatter diffraction (EBSD), transmission Kikuchi diffraction (TKD), and transmission electron microscopy (TEM). The conventional EBSD and TKD analysis results could provide misorientation angles smaller than 2°, while the resolution mainly depends on the specimen quality and scanning step size, and so on. A TEM technique with higher spatial resolution provides accurate information between adjacent dislocation cells with misorientation angles smaller than 1°. This study presents evidence that the TEM method is the better and more precise analytical method for the misorientation measurement of the cellular structures and provides insights into measuring the small misorientation angles between adjacent dislocation cells and nanograins in nanostructured metals and alloys with ultrafine-grained microstructures.

On the correspondence of bump relief on the surface of materials processed with low-energy high-current electron beam to their grain structure

One of the features that appears on the pre-polished surface of metals and alloys as a result of processing with low-energy high-current electron beam is a bump surface relief with the bump size varying from several tens to several hundred nanometers. Some researchers consider these bumps as the trace of the grain structure of the near-surface modified layer of material. The aim of the present work was to show experimental results proving that the bump relief is not related to the grain size in the near-surface layer. The microstructure was studied using reliable complementary methods of transmission electron microscopy and backscattered electron diffraction using Inconel 718 alloy and stainless steel obtained by additive manufacturing and processed with low-energy high-current electron beam.

Nanozinc ferrites @ silica as efficient adsorbent for dye removal from wastewater: synthesis and adsorption studies

AbstractThe precipitation process was successfully employed to prepare ZnFe2O4 and ZnFe2O4@SiO2 nanoparticles. The synthesized nanoadsorbents were characterized employing transmission electron microscopy (TEM), X-ray diffraction (XRD), and Brauner-Emmett and Teller (BET) methods. The potential adsorption capacities of the generated nanoparticles were assessed under various conditions, including pH, starting dye concentration, contact time, and temperature. The adsorption efficiency of ZnFe2O4@SiO2 nanoparticles (95%) was higher than ZnFe2O4 (93%). The adsorption data were described using Langmuir, Freundlich, Temkin, and Dubinin-Kaganer-Radushkevich (DKR) isotherm models. The methylene blue (MB) removal kinetics by ZnFe2O4 and ZnFe2O4@Silica nanoparticles were evaluated using linear pseudo-first-order (PFO) and pseudo-second-order (PSO) models. The removal fitted to pseudo-second-order (PSO) models as the correlation coefficient (R2) value was (0.9994). The Boyd model may be used to validate the kinetics data, and it can be deduced that the rate-determining phase was not intra-particle diffusion, but rather the hypothesized adsorption process was endothermic and spontaneous in nature. Based on the findings, ZnFe2O4@silica is an adsorbent material that may be useful in removing methylene blue from aqueous solutions.

Silver Nanoparticles Decorated in In Situ Reduced Graphene Oxide Nanohybrids Improved Properties in Poly(vinylidene fluoride)/Poly(methyl methacrylate) Blends

In this paper, reduced graphene oxide decorated with silver nanoparticle (rGO-Ag) nanohybrids were prepared using an environmentally friendly approach and incorporated as reinforcement in poly(vinylidene fluoride)-poly(methyl methacrylate) blends via a melt mixing process. The microstructure of rGO-Ag nanohybrids and its effect on the microstructure, mechanical, thermal, and electrical properties of the PVDF/PMM/rGO-Ag was studied using Fourier transform infrared (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), tensile, thermogravimetric analysis (TGA), and impedance spectroscopy methods. FTIR and TEM analysis confirmed that rGO-Ag successfully synthesized and Ag nanoparticles are located on the rGO surface. The tensile analysis demonstrated that incorporating 1 wt.% of rGO-Ag in PVDF/PMMA blend increases Young’s modulus and strength of nanocomposite up to 31% and 35%, respectively. The Halpin-Tsai model was also used for PVDF/PMMA/rGO-Ag nanocomposites, and the results confirmed that this model works well to predict the tensile modulus. Impedance spectroscopy analysis showed that the presence of rGO-Ag nanohybrids in PVDF/PMMA blend effectively enhanced the conductivity of PVDF/PMMA blend. TGA results demonstrated that the presence of rGO-Ag nanohybrids enhanced the thermal stability of nanocomposites and increased the degradation temperature of PVDF/PMMA/rGO-Ag nanocomposites in the range of 20°C compared to PVDF/PMMA blend.

Using the IL-TEM Technique to Understand the Mechanism and Improve the Durability of Platinum Cathode Catalysts for Proton-Exchange Membrane Fuel Cells.

Proton-exchange membrane fuel cells are one of the most promising energy conversion technologies for both automotive and stationary applications. Scientists are testing a number of solutions to increase the durability of cells, especially catalysts, which are the most expensive component. These solutions include, among others, the modification of the composition and morphology of supported nanoparticles, the platinum-support interface, and the support itself. A detailed understanding of the mechanism of platinum degradation and the subsequent improvement of the durability of the entire cell requires the development of methods for effectively monitoring the behavior of catalytic nanoparticles under various cell operating conditions. The Identical-Location Transmission Electron Microscopy (IL-TEM) method makes it possible to visually track structural and morphological changes in the catalyst directly. Because the tests are performed with a liquid electrolyte imitating a membrane, they provide better control of the degradation conditions and, consequently, facilitate the understanding of nanoparticle degradation processes in various operating conditions. This review is primarily intended to disseminate knowledge about this technique to scientists using electron microscopy in the study of energy materials and to draw attention to issues related to the characterization of the structure of carbon supports.

The effect of boron on the structure and lattice parameters of diamond single crystals

Boron doped diamonds (BDD) with boron concentration above 1019 at./cm3, grown under conditions of high isostatic pressure by the temperature gradient method, were studied by Transmission Electron Microscopy methods, EELS analysis and X-ray diffraction analysis. It was shown that boron is distributed unevenly in the grown crystal. It was found that in places of maximum boron content, interplanar distances d111 increase from 0.206 to approximately 0.2065 nm. Parallel bands were discovered, the boundaries of which are fragments of the intermediate carbon phase (ICP-phase). Numerous twins along the {111} plane, as well as fragments of rhombohedral 9R phase, were discovered.

Identification of the murine osteoblastic cell MC3T3-E1 as a permissive cell line in response to lumpy skin disease virus

Lumpy skin disease virus (LSDV) is a rapidly emerging pathogen in China. Screening suitable cells for LSDV replication is vital for future research on pathogenic mechanisms and vaccine development. Previous comparative studies have identified that the rodent-derived BHK21 is a highly susceptible cell model to LSDV infection. Using western blot, indirect immune-fluorescence assay, flow cytometry, and transmission electron microscopy methods, this study is the first to identify the murine osteoblastic cell line MC3T3-E1 as a novel permissive cell model for LSDV infection. The establishment of MC3T3-E1 as a suitable infectious cell model enhances our understanding of the species range and cell types of the permissive cells and nonpermissive that support LSDV replication. It is helpful to accelerate future research on the pathogenesis, clinical application, and vaccine development of LSDV.

Structure of root nodules in <i>Laburnum anagyroides</i> Medik.

The structure of the <i>Laburnum anagyroides</i> root nodules was studied by means of classical light and transmission electron microscopy methods. The ability of cross-inoculation and effective nodulation by rhizobial microsymbionts, effective in other genistean species, was not confirmed in <i>L. anagyroides</i>. However, the seedlings were successfully albeit ineffectively nodulated by non-identified rhizobia from soil sampled under established <i>L. anagyroides</i> trees. The microscopic (ultra)structure of these nodules met the basic criteria of genistoid nodules: their meristem was apically positioned and contained two domains (infected and non-infected one), non-bacteroidal rhizobia persisted in apoplast enclaves, and intra-nodule rhizobial infection was passed from cell to cell by host cell division and not by infection threads. The developmental disturbances detected in the nodules (primarily, formation of multi-bacteroid sacs instead of typical single-bacteroid symbiosomes and proliferation apoplast enclaves with accompanying cell wall discontinuities) suggested that the host plant incorrectly recognized the microsymbiont used in the present study.

The superiority of the photocatalytic and antibacterial performance of mechanochemically synthesized CdS nanoparticles over solvothermal-prepared ones

In this work, we have developed a facile, dry, and environmentally friendly mechanochemical method for the synthesis of cadmium sulfide (m-CdS) nanoparticles in a planetary ball mill using non-toxic precursors. Thiourea was for the first time used as a precursor of sulfide ion in room temperature solid state ball milling synthesis. For comparison of the mechanochemical approach with others, cadmium sulfide nanoparticles were also prepared using the solvothermal method (s-CdS). The crystal structure of cadmium sulfide nanoparticles was studied by XRD, the qualitative chemical band properties were examined by Raman scattering and x-ray photoelectron spectroscopy analysis, and particle morphology and microstructure were investigated by scanning electron microscopy and transmission electron microscopy methods. The sizes of the m-CdS nanoparticles had 5–6 nm in diameter, which is 10 times smaller than the diameter of s-CdS nanorods. The photocatalytic activities of as-prepared cadmium sulfide nanoparticles on the dye degradation and hydrogen production by water splitting were evaluated and the antibacterial activities were also tested. The photocatalytic activity of m-CdS was superior to that of s-CdS in the degradation of Orange II under visible light irradiation. Better results for m-CdS were also evidenced in photocatalytic experiments on hydrogen generation. The maximum rate of hydrogen evolution for m-CdS was 191.9 µmolg−1h−1 at the 120th min,while this indicator for s-CdS was only 58.0 µmolg−1h−1 at the same irradiation time.The better effect of m-CdS was evidenced also in an antibacterial study (namely against gram-positive bacteria).