Transmission Electron Microscopy Image Analysis Research Articles

Intensified inactivation efficacy of pulsed ohmic heating for pathogens in soybean milk due to sodium lactate

Pulsed ohmic heating (POH) is a promising alternative to conventional heat processing for microbial safety. It has been reported that the efficacy of POH depends on the concentration of electrolytes. This research investigated the effect of sodium lactate as an electrolyte on the efficacy of POH with respect to the heating rate and inactivation of pathogens in PBS and soybean milk. When PBS and soybean milk with 0–3% sodium lactate were subjected to POH, as the sodium lactate content increased, the electrical conductivity increased, thereby accelerating the heating rate of POH. For instance, the heating rate of POH was 0.3 and 1.3°C/s for 0 and 3% of sodium lactate in soybean milk. Reductions in pathogens increased as the sodium lactate content increased. When 3% of sodium lactate was added to PBS or soybean milk, the bacterial reduction was more than 1 log unit compared to 0%. We hypothesized that sodium lactate intensified the damage to bacterial membrane by accelerating the heating rate of POH and amplifying the electric current; thus, the extent of bacterial cell membrane damage was determined using propidium iodide (PI) and transmission electron microscopy (TEM). The PI uptake values of pathogens significantly (P < 0.05) increased as the sodium lactate content increased, indicating that the membrane damage increased in proportion to the sodium lactate content. Furthermore, the analysis of TEM images of Escherichia coli O157:H7 and Listeria monocytogenes showed fatal morphological cell rupture at 3% sodium lactate. After soybean milk with 0–3% sodium lactate was treated with POH, no electrode corrosion was observed, and pH and color of samples were not changed. Thus, this research corroborated that sodium lactate intensifies the efficacy of POH without electrode corrosion and quality degradation of soybean milk.

Mori-Tanaka-based statistical methodology to compute the effective Young modulus of polymer matrix nano-composites considering the experimental quantification of nanotubes dispersion and alignment degree

This paper presents a Mori-Tanaka-based statistical methodology to predict the effective Young modulus of carbon nanotubes (CNTs)-reinforced composites considering three variables: weight content, reinforcement dispersion and orientation. Last two variables are quantified by two parameters, namely, free-path distance between nano-reinforcements and orientation angle regarding the loading direction. To validate the present methodology, samples of multi-walled CNTs (MWCNTs)-reinforced polyvinyl alcohol (PVA)-matrix composite were manufactured by mixing solution. The MWCNT/PVA Young modulus was measured by nano-indentation, while the MWCNTs Young modulus was quantified by micro-Raman spectroscopy. Both stretched and unstretched composite specimens were fabricated. Transmission electron microscopy (TEM) and in-plane image analysis were used to obtain fitting coefficients of log-normal frequency distribution functions for the free-path distance and orientation angle. It was evidenced that numerical results fit well to measured values of effective Young modulus of MWCNTs and MWCNT/PVA, with exception of some particular cases where significant differences were found. Microstructural heterogeneities, cluster formation, polymer chains alignment, errors associated with the dispersion, orientation and mechanical characterization procedures, as well as idealization and statistical errors, were identified as possible causes of these differences. Finally, using the proposed methodology and the dispersion and orientation distribution functions experimentally obtained, the effective Young modulus is estimated for three kinds of thermoplastic matrices (polyvinyl alcohol, polyethylene ketone, and ultra-high molecular weight polyethylene) with different kinds of nanotubes (single wall, double wall, and multi-walled), at different weight contents, finding the superior mechanical performance for double-walled CNTs-reinforced composites and the lower one for multi-walled CNTs-reinforced ones.

In-vitro Antimicrobial Activity of Green Synthesised Silver Nanoparticles of Leaf Extract of Rhinacanthus nasutus against Bacterial Food Borne Pathogens

Introduction: Green synthesis of nanoparticles plays a major role in the control of virulent pathogens due to their ecofriendly, depreciated cost and naive nature. This peculiarity of plant based nanoparticle synthesis accomplishes them as fleeting development in nanobiotechnology. Rhinacanthus nasutus is one such plant, which is generally known as snake jasmine has prodigious medicinal properties to explore. Aim: The intent of this study was to harmonise silver nanoparticles (AgNPs) from leaves extract of Rhinacanthus nasutus (Snake jasmine) and interrogate its vitality against virulent bacteria secluded from food. Materials and Methods: The in-vitro study was conducted in Department of Microbiology at Muthayammal College of Arts and Science, Namakkal, Tamil Nadu, India, during November 2018 to November 2020. Nanoparticles were harmonised using 2 mM silver nitrate with leaves extract of Rhinacanthus nasutus which was then characterised by Ultraviolet-visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray (EDX) analysis and Transmission Electron Microscopy (TEM) imaging and Energy Dispersive X-Ray (EDX) analysis. Followed with this the antibacterial activity of silver nanoparticles was evaluated by agar well diffusion method against virulent bacteria isolated from food samples. Furthermore AgNPs was subjected to antibiofilm activity. Origin tool and Microsoft word 2010 were used for statistical analysis. Results: The green synthesis of silver nanoparticles possessed antibacterial activity against antibiotic resistant, biofilm and beta-lactamase producing Escherichia coli, Enterococcus spp, Klebsiella spp, Pseudomonas spp, Proteus spp, Staphylococcus spp, Salmonella spp and Shigella spp. Together with this the amalgamated AgNPs also exhibited antibiofilm activity in all the isolates. The better results of antibiofilm activity was observed against Salmonella species (74.1%). Conclusion: This study divulges the presence of substantial antibacterial activity of green synthesis of silver nanoparticles of Rhinacanthus nasutus leaves extract against virulent bacterial species. Hence, it can be explored and exploited for the formulation of new antimicrobial against biofilm and betalactamase producing bacterial isolates due to its modest and ecofriendly nature.

The Nuclear Function of IL-33 in Desensitization to DNA Damaging Agent and Change of Glioma Nuclear Structure.

Glioma, the most common subtype of primary brain tumor, is an aggressive and highly invasive neurologically tumor among human cancers. Interleukin-33 (IL-33) is considered as a dual functional cytokine, an alarmin upon tissue damage and a nuclear chromatin-associated protein. Despite that, IL-33 is known to foster the formation of the inflammatory tumor microenvironment and facilitate glioma progression, evidence showing nuclear IL-33 function is still poor. In this study using lentivirus-mediated IL-33 gene knockdown (IL33KD) and IL-33 overexpression (IL33oe) in rat C6 glioma cells and human glioma cell lines (U251MG and U87MG), we found that IL33oe-glioma cells had resistance to the insults of the alkylating agent, temozolomide (TMZ), possibly because of the increased expression of DNA repair genes (i.e., BRCA1, BRCA2, Rad51, FANCB, and FANCD) in IL33oe-glioma cells. Alternatively, examination of glioma nuclear shape from transmission electron microscopy (TEM) imaging analysis and immunofluorescence for histone protein H2A staining showed that IL33KD attenuated the abnormal cancerous nuclear characteristic, such as indentation, long clefts, and multiple nucleoids. Yet, IL33oe promoted the changes in glioma nuclear shapes, such as the formation of multiple lobes. We further found that histone proteins, H2A and H3, were reduced in IL33KD glioma cells. The non-histone DNA-binding nucleoproteins, the high mobility group A1 (HMGA1) and HMGA2, were also downregulated by IL33KD. In contrast, IL33oe increased H2A and H3 proteins and HMGA1 and HMGA2 in glioma cells. Altogether, the upregulation of nuclear IL-33 expression was along with an increase in the expression of DNA repair genes, contributing to the desensitization of glioma cells to DNA damaging agents. Moreover, nuclear IL-33 proteins in cooperation with chromatin-associated proteins regulate glioma nuclear structure, which might be crucial for glioma progression and malignancy.

Roll-to-Roll Manufactured Sensors for Nitroaromatic Organophosphorus Pesticides Detection

A fully roll-to-roll manufactured electrochemical sensor with high sensing and manufacturing reproducibility has been developed for the detection of nitroaromatic organophosphorus pesticides (NOPPs). This sensor is based on a flexible, screen-printed silver electrode modified with a graphene nanoplatelet (GNP) coating and a zirconia (ZrO2) coating. The combination of the metal oxide and the 2-D material provided advantageous electrocatalytic activity toward NOPPs. Manufacturing, scanning electron microscopy-scanning transmission electron microscopy image analysis, electrochemical surface characterization, and detection studies illustrated high sensitivity, selectivity, and stability (∼89% current signal retention after 30 days) of the platform. The enzymeless sensor enabled rapid response time (10 min) and noncomplex detection of NOPPs through voltammetry methods. Furthermore, the proposed platform was highly group-sensitive toward NOPPs (e.g., methyl parathion (MP) and fenitrothion) with a detection limit as low as 1 μM (0.2 ppm). The sensor exhibited a linear correlation between MP concentration and current response in a range from 1 μM (0.2 ppm) to 20 μM (4.2 ppm) and from 20 to 50 μM with an R2 of 0.992 and 0.991, respectively. Broadly, this work showcases the first application of GNPs/ZrO2 complex on flexible silver screen-printed electrodes fabricated by entirely roll-to-roll manufacturing for the detection of NOPPs.

Green Synthesis of Silver Nanoparticles using Delonix regia Extract, Characterization and its Application as Adsorbent for Removal of Cu (II) Ions from Aqueous Solution

In this research synthesis of silver nanoparticles by a green method is studied. The high importance of silver nanoparticles using extract of Delonix regia (DREAgNs) is due to their unique properties, such as non-expensive, easily available and have application in water treatment. Synthesized silver nanoparticles AgNPs were characterized using UV-Visible Spectrophotometer to indicate the synthesis of AgNPs by green methods. The maximum absorbance of UV-Vis. analysis at wavelength 464 nm. (FT-IR) spectra to indicate the functional groups of phytochemical compounds at Delonix regia extract (DRE) and the silver nanoparticles (DREAgNPs) and also shows the role of active chemical constituents in stabilization and reduction of (DREAgNPs). Based on the transmission electron microscopy image analyses (TEM) confirmed the formation of spherical DREAgNPs with a particle size range of 20-50 nm with an average particle size of 35 nm. The Cu2+ ion adsorption process was studied by (DREAgNPs). The Cu2+ ions removal efficiency (R. E.) is 88.4 % at an initial concentration 15 ppm. Removal efficiency (R. E.) decreases as the Cu2+ ion concentration increases. Furthermore, thermodynamic studies confirmed that the biosorption process was endothermic and the positive value of ΔG° is quite common when an ion-exchange mechanism applies in the biosorption. The Positive value of ΔS◦ suggested an increase in randomness during the biosorption. The Freundlich isotherm has a good fit with the experimental data (R2 =0.99) compared to Langmuir isotherm (R2 = 0.90). This study shows that DREAgNPs are available, low cost, effective and environment friendlly biosorbent for the removal of Cu2+ ions from aqueous environment.

Microstructural stability of TMS-238TM Ni-base superalloy during long-term exposure at high temperature

The microstructure evolution in Re–Ru containing high generation Ni-base single crystal superalloy has been investigated during long-term isothermal exposure at 1000°C. The chemical and physical characteristics are determined by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) measurements. In addition to the initial γ/γ’ phase structure, formation of HCP-structured Re–Ru–Ni-rich phase is confirmed. Based on high-resolution TEM imaging and phase structure analysis the theoretical atomistic model presenting the interfaces between the phases was constructed and evaluated with respect to precipitation kinetics. Growth of plate-like precipitates occurs mainly through the plate edge area due to stacking fault sequences between the surrounding matrix and the precipitates, while thickening is very limited due to good coherency with the surrounding phase in the longitudinal direction.

Environmental-friendly synthesis of Au-Ag alloy nanoparticles using Anethum graveolens leaf extract and their application to Surface Enhanced Raman Scattering (SERS)

We report an Environmental-friendly method for the synthesis of Au-Ag alloy nanoparticles (ANPs) by using Anethum graveolens fresh leaf extract as a reducing and stabilizing agent. The precursor solutions of Au (HAuCl4: 3H2O), Ag (AgNO3) and leaf extract were mixed by varying molar ratios and heated with continuous stirring at 70℃ for an hour leads a formation of Au-Ag ANPs with different atomic compositions. The periodic observation of colour changes indicated the formation of Au-Ag ANPs and got confirmed by the measurement of UV-Vis spectroscopy. The synthesized Au-Ag ANPs were characterized for morphological and elemental composition using Transmission Electron Microscopy (TEM) in conventional and scanning TEM (STEM) mode. The TEM image analysis shows that the synthesized Au-Ag ANPs were found to be in spherical shape with a broad size distribution with a mean size of 23 ± 18 nm. The energy dispersive X-ray (EDX) spectrometry in the STEM mode confirms the formation of Au-Ag ANPs . To show that these biosynthesized Au-Ag ANPs can be used as SERS (Surface Enhanced Raman Scattering) substrates, we carried out SERS studies using Crystal Violet (CV) and Rhodamine 6G (R6G) as test molecules by using 514.5 nm laser excitation wavelength. The detection level achieved was 50µM of CV and R6G, which would lead to exploring biosensing applications.

Analysis of TEM images of metallic nanoparticles using convolutional neural networks and transfer learning

Convolutional neural networks (CNNs) pretrained by transfer learning were applied to the analysis of transmission electron microscopy (TEM) images of nanoparticles. Specifically, TEM images of non-magnetic Pt nanoparticles dispersed on a thin TiO2 crystal foil were classified using CNNs. Although the number of learning data (50≤ N≤350) was several orders of magnitude smaller than the quantities normally employed in conventional CNN analyses, the present CNN model was able to carry out image classification with 94% accuracy (average of 25 results) after the convolutional layers were pretrained by transfer learning and fine tuning. This method represents a promising tool for TEM studies of both non-magnetic and magnetic nanoparticles which make emergence of rich material functions.

Deep Learning Segmentation of Complex Features in Atomic-Resolution Phase-Contrast Transmission Electron Microscopy Images.

Phase-contrast transmission electron microscopy (TEM) is a powerful tool for imaging the local atomic structure of materials. TEM has been used heavily in studies of defect structures of two-dimensional materials such as monolayer graphene due to its high dose efficiency. However, phase-contrast imaging can produce complex nonlinear contrast, even for weakly scattering samples. It is, therefore, difficult to develop fully automated analysis routines for phase-contrast TEM studies using conventional image processing tools. For automated analysis of large sample regions of graphene, one of the key problems is segmentation between the structure of interest and unwanted structures such as surface contaminant layers. In this study, we compare the performance of a conventional Bragg filtering method with a deep learning routine based on the U-Net architecture. We show that the deep learning method is more general, simpler to apply in practice, and produces more accurate and robust results than the conventional algorithm. We provide easily adaptable source code for all results in this paper and discuss potential applications for deep learning in fully automated TEM image analysis.

Experimental investigation into the oxidation reactivity, morphology and graphitization of soot particles from diesel/n-octanol mixtures

Aiming to investigate the impacts of n-octanol addition on the oxidation reactivity, morphology and graphitization of diesel exhaust particles, soot samples were collected from a four-cylinder turbocharged diesel engine fueled with D100 (neat diesel fuel), DO15 (85% diesel and 15% n-octanol, V/V) and DO30 (70% diesel and 30% n-octanol, V/V). All tests were conducted at two engine speeds of 1370 and 2150 r/min under a fixed torque of 125 N·m. The soot properties were characterized by thermogravimetric analyzer (TGA), transmission electron microscopy (TEM) and Raman spectroscopy (RS). The higher volatile organic fraction content, lower soot oxidation temperatures and lower activation energy from TGA results indicated that both the increasing n-octanol concentration and engine speed enhanced the soot oxidation reactivity. Additionally, quantitative analysis of TEM images showed that the soot derived from DO30 had the smallest primary particle diameters and fractal dimension, followed by those of soot produced by DO15 and D100. The RS results demonstrated that the n-octanol addition and higher engine speed led to a larger D1-FWHM (D1-full width at half maximum), AD1/AT (area ratio of D1 band and the total spectral) and AD3/AT (area ratio of D3 band and the total spectral) as well as a smaller La (crystallite width), revealing a lower degree of graphitization. Furthermore, the correlations between characterization parameters of soot properties and reactivity were nonlinear.

Effective adsorptive removal of anionic dyes from aqueous solution

AbstractCongo Red (CR) and Reactive Black 5 (RB5) anionic dyes were removed from aqueous solution using Porous Magnetite Fe3O4 nanospheres (PMNs) as a high‐performance adsorbent. Various methods, such as Fourier transform infrared spectroscopy and X‐ray diffraction, were used to classify the synthesized PMNs. The Brunauer Emmett‐Teller (BET) method was used to calculate the sample's high specific surface area of 143.65 m2.g‐1, as well as its pore volume and pore size. The PMNs have a very uniform spherical morphology, with an average particle size of 25.84 nm, as revealed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) image analysis. Variables such as initial pH, adsorbent dosage, contact time, and temperature were investigated to determine optimal adsorption conditions for the extraction of Congo Red (CR) and Reactive Black 5 (RB5) from aqueous solutions. The optimal pH for extracting the anionic dyes tested from water solutions was 3 and 4 for CR and RB5, respectively. The maximum adsorption potential of the CR and RB5 dyes, respectively, was 1621.59 and 1070 mg.g‐1. pH, temperature, initial concentration, contact time, salinity, and PMNs dosing were all studied in depth. Since the PMNs Zero‐charge point (pHPZC) equals 4.3, these dyes were ideal for adsorption at an acid pH. The Langmuir, Freundlich, Dubinin ‐ Radushkevich, and Temkin adsorption isotherms were used to determine adsorption results. For both dyes, the adsorption isotherm was fitted to the Langmuir model. The mean adsorption energy (Ea) for CR and RB5, respectively, is 20.2 and 24.8 kJ.mol‐1, suggesting a chemisorption mechanism. The kinetics of adsorption was discovered to adopt a pseudo‐second‐order kinetic model. Thermodynamic experiments confirmed that the adsorption mechanism is endothermic and spontaneous. They experimented with ethanol as a solvent for desorption of adsorbed anionic dyes.

Biosynthesis of silver nanoparticles using Haloferax sp. NRS1: image analysis, characterization, in vitro thrombolysis and cytotoxicity

Haloferax sp strain NRS1 (MT967913) was isolated from a solar saltern on the southern coast of the Red Sea, Jeddah, Saudi Arabia. The present study was designed for estimate the potential capacity of the Haloferax sp strain NRS1 to synthesize (silver nanoparticles) AgNPs. Biological activities such as thrombolysis and cytotoxicity of biosynthesized AgNPs were evaluated. The characterization of silver nanoparticles biosynthesized by Haloferax sp (Hfx-AgNPs) was analyzed using UV–vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The dark brown color of the Hfx-AgNPs colloidal showed maximum absorbance at 458 nm. TEM image analysis revealed that the shape of the Hfx-AgNPs was spherical and a size range was 5.77- 73.14 nm. The XRD spectra showed a crystallographic plane of silver nanoparticles, with a crystalline size of 29.28 nm. The prominent FTIR peaks obtained at 3281, 1644 and 1250 cm− 1 identified the Functional groups involved in the reduction of silver ion reduction to AgNPs. Zeta potential results revealed a negative surface charge and stability of Hfx-AgNPs. Colloidal solution of Hfx-AgNPs with concentrations ranging from 3.125 to 100 μg/mL was used to determine its hemolytic activity. Less than 12.5 μg/mL of tested agent showed no hemolysis with high significant decrease compared with positive control, which confirms that Hfx-AgNPs are considered non-hemolytic (non-toxic) agents according to the ISO/TR 7405-1984(f) protocol. Thrombolysis activity of Hfx-AgNPs was observed in a concentration-dependent manner. Further, Hfx-AgNPs may be considered a promising lead compound for the pharmacological industry.

Influence of flexoelectric effects on domain switching in ferroelectric films

Flexoelectricity has been shown to be an effective strategy to modulate the polarization configurations, domain structures, and physical properties in nanoscale ferroelectric thin films. However, the relations between the domain switching processes and flexoelectric effects remain elusive, which is essential for the design of nanoscale ferroelectric electric devices. In this work, strain-gradient and normal PbTiO3 films are fabricated and investigated to resolve this elusive relationship. By using large-scale and local piezoelectric force microscopy characterization, the ferroelectric domain switching in strain-gradient PbTiO3 films is found to be hard and hindered under applied electric fields compared with the normal ones. Successive atomic-scale scanning transmission electron microscopy imaging analysis manifests that the domains in the strain-gradient PbTiO3 films are stabilized by an additional effective strain gradient-induced flexoelectric field, which was introduced by negative pressure originated from vertically distributed Pb-rich anti-phase domains. This study proposes an effective method to stabilize the ferroelectric polarization in nanoscale ferroelectric films, thus facilitate improving the reliability of ferroelectric electronic devices.

Synergic grain boundary segregation and precipitation in W- and W-Mo-containing high-entropy borides

The structures of W- and W-Mo-containing high-entropy borides (HEBs) are systematically studied by combining atomic-resolution transmission electron microscopy imaging, electron diffraction, and chemical analysis. We reveal that W or W-Mo addition in HEBs leads to segregation of these elements to the grain boundaries (GBs). In the meantime, W- or W-Mo-rich precipitates also form along the GBs. Crystallographic analysis and atomic-scale imaging show that the GB precipitates in both W- and W-Mo-containing HEBs have a cube-on-cube orientation relationship with the matrix. With further strain analysis, the coherency of the precipitate/matrix interface is validated. Nanoindentation tests show that the simultaneous GB segregation and coherent precipitation, as a supplement to the grain hardening, provide additional hardening of the HEBs. Our work provides an in-depth understanding of the GB segregation and precipitation behaviors of HEBs. It suggests that GB engineering could be potentially used for optimizing the performance of high-entropy ceramics.

AutoDetect-mNP: An Unsupervised Machine Learning Algorithm for Automated Analysis of Transmission Electron Microscope Images of Metal Nanoparticles.

The synthesis quality of artificial inorganic nanocrystals is most often assessed by transmission electron microscopy (TEM) for which high-throughput advances have dramatically increased both the quantity and information richness of metal nanoparticle (mNP) characterization. Existing automated data analysis algorithms of TEM mNP images generally adopt a supervised approach, requiring a significant effort in human preparation of labeled data that reduces objectivity, efficiency, and generalizability. We have developed an unsupervised algorithm AutoDetect-mNP for automated analysis of TEM images that objectively extracts morphological information on convex mNPs from TEM images based on their shape attributes, requiring little to no human input in the process. The performance of AutoDetect-mNP is tested on two data sets of bright field TEM images of Au nanoparticles with different shapes and further extended to palladium nanocubes and cadmium selenide quantum dots, demonstrating that the algorithm is quantitatively reliable and can thus serve as a generalizable measure of the morphology distributions of any mNP synthesis. The AutoDetect-mNP algorithm will aid in future developments of high-throughput characterization of mNPs and the future advent of time-resolved TEM studies that can investigate reaction mechanisms of mNP synthesis and reactivity.

Genome-resolved metagenomics reveals site-specific diversity of episymbiotic CPR bacteria and DPANN archaea in groundwater ecosystems

Candidate phyla radiation (CPR) bacteria and DPANN archaea are unisolated, small-celled symbionts that are often detected in groundwater. The effects of groundwater geochemistry on the abundance, distribution, taxonomic diversity and host association of CPR bacteria and DPANN archaea has not been studied. Here, we performed genome-resolved metagenomic analysis of one agricultural and seven pristine groundwater microbial communities and recovered 746 CPR and DPANN genomes in total. The pristine sites, which serve as local sources of drinking water, contained up to 31% CPR bacteria and 4% DPANN archaea. We observed little species-level overlap of metagenome-assembled genomes (MAGs) across the groundwater sites, indicating that CPR and DPANN communities may be differentiated according to physicochemical conditions and host populations. Cryogenic transmission electron microscopy imaging and genomic analyses enabled us to identify CPR and DPANN lineages that reproducibly attach to host cells and showed that the growth of CPR bacteria seems to be stimulated by attachment to host-cell surfaces. Our analysis reveals site-specific diversity of CPR bacteria and DPANN archaea that coexist with diverse hosts in groundwater aquifers. Given that CPR and DPANN organisms have been identified in human microbiomes and their presence is correlated with diseases such as periodontitis, our findings are relevant to considerations of drinking water quality and human health.

Cuminum cyminum L.-Mediated Synthesis of Silver Nanoparticles: Their Characterization and Effect on Formalin-Induced Nociceptive Response in Male Rats.

In this study, a simple, low-cost, rapid, and eco-friendly approach for the biosynthesis of silver nanoparticles (AgNPs) using the aqueous extract of Cuminum cyminum L. (cumin) seed (CcAgNPs) was developed. Also, the anti-nociceptive properties of these synthesized AgNPs were evaluated in vivo. The CcAgNPs characterized using Ultraviolet-visible (UV-Vis) spectrophotometer, X-ray diffraction analysis (XRD), Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM). The analysis of phytochemical components in the aqueous extract of cumin seeds showed high concentrations of total phenols and ascorbic acid and low concentrations of total flavonoids. The analysis of phytochemical components and FTIR spectroscopy confirmed the presence of functional groups responsible for the bioreduction of Ag+ to AgNPs. The UV-Vis absorbance spectrum of CcAgNPs showed a maximum wavelength at 442nm. The analysis of TEM images showed a spherical shape with a size of less than 50nm, while XRD spectra revealed the crystallinity of CcAgNPs. The analysis of anti-nociceptive properties of CcAgNPs showed that the first phase of formalin-induced pain was significantly reduced in the groups receiving 200, 500, and 1000mg/kg CcAgNPs compared with the controls and the group receiving 300mg/kg of sodium salicylate (SS300). The second phase of formalin pain was also significantly reduced in the groups receiving 200 and 500mg/kg CcAgNPs compared to the controls and SS300 group. Overall, we introduced a new AgNPs synthesized from cumin seeds (CcAgNPs) and showed their anti-nociceptive properties in the formalin-induced pain.

Microstructural evolution in self-catalyzed GaAs nanowires during in-situ TEM study

The microstructural evolutions in self-catalyzed GaAs nanowires (NWs) were investigated by using in situ heating transmission electron microscopy (TEM). The morphological changes of the self-catalyst metal gallium (Ga) droplet, the GaAs NWs, and the atomic behavior at the interface between the self-catalyst metal gallium and GaAs NWs were carefully studied by analysis of high-resolution TEM images. The microstructural change of the Ga-droplet/GaAs-NWs started at a low temperature of ∼200 °C. Formation and destruction of atomic layers were observed at the Ga/GaAs interface and slow depletion of the Ga droplet was detected in the temperature range investigated. Above 300 °C, the evolution process dramatically changed with time: The Ga droplet depleted rapidly and fast growth of zinc-blende (ZB) GaAs structures were observed in the droplet. The Ga droplet was completely removed with time and temperature. When the temperature reached ∼600 °C, the decomposition of GaAs was detected. This process began in the wurtzite (WZ) structure and propagated to the ZB structure. The morphological and atomistic behaviors in self-catalyzed GaAs NWs were demonstrated based on thermodynamic considerations, in addition to the effect of the incident electron beam in TEM. Finally, GaAs decomposition was demonstrated in terms of congruent vaporization.

Magnetite-Functionalized Horse Dung Humic Acid (HDHA) for the Uptake of Toxic Lead(II) from Artificial Wastewater

Magnetite-functionalized horse dung humic acid (HDHA) has been successfully prepared by the coprecipitation method, and the as-prepared adsorbent (MHDHA) has been applied as an easy-handling adsorbent for toxic Pb(II) in artificial wastewater. The MHDHA was characterized by Fourier transform-infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), and vibrating sample magnetometer (VSM). The FT-IR study showed that the MHDHA had the characteristics peaks of HA and Fe-O stretching. The XRD analysis revealed that the MHDHA had the [Formula: see text] characteristic for magnetite. The TEM image and EDX analysis exhibited that the MHDHA with an average size of ∼14 nm was partially aggregated and contained ([Formula: see text]) 9.89% carbon, 2.89% nitrogen, and 32.74% oxygen based on functional groups of HDHA. The stability improvement of MHDHA was showed by decreasing HDHA dissolved from 95% to less than 30% at pH 12 after magnetite functionalization. The post-adsorption handling improvement was evidenced by easy and quick retraction by an external magnet with a 62.95 emu/g magnetic strength value. The adsorption capacities were influenced by the pH and ionic strength, whilst the adsorption rates were well simulated by the Ho pseudo-second-order model. The removal uptake of Pb(II) ions increased when the initial concentration was increased and fitted well with the Langmuir isotherm model when the monolayer adsorption capacity was [Formula: see text] (equal to 57.64 mg/g). The value of Dubinin-Radushkevich adsorption energy ([Formula: see text]) found in this study was 14.78 kJ/mol, which implied that ion exchange is the main mechanism involved in the adsorption process. The regeneration studies of MHDHA show that there was no significant change in composition, morphology, crystallinity, and functional group after five consecutive cycles of the adsorption-desorption process.